Zelda idea

The Legend of Zelda: Fierce Diety
Based in Termina, a somewhat return-to-formula (concerning map building) with a small smattering of the good ideas BotW introduces. Rather than pure open world, we have a simply massive ever changing "Hyrule Field" (Termina) area with self contained built-areas in it and on the perimeter. A masks based game where this time /everything/ is a mask.
The cool part however; is that I would also introduce the "Face Sword". This guy would also double as the classic companion character. A sword that has a blank face on its guard that the various masks in the game could be equipped to, giving it various transformations, powers, and puzzle solving utilities. You can even use 2 masks at once by equipping one on Link, one on the sword. The game would be gloriously difficult in places where you had to nimbly switch between masks both on Link and the sword in a very short span of time to use the very subtle effects each variety imparts in a given situation.
Ex: One mask to raise a cube of earth from the ground, then a fire mask to strike only the left side of that cube (aim carefully), a time-slow mask on Link so you can run to the other side before the fire runs out, and put the bunny hood/or a new 'speedy' mask on the sword whose now-fast thrusts are the only thing that can hit every puzzle slot in time. Have enemies in certain challenge modes/areas require things like this as well. Almost every mask in the game would have associated objects upon which to deploy their effects. (Objects meant in the programmers sense of that word) The sum of these objects would consist the puzzles. "Objects" would be either concrete key furnishings on the environment or states applied to the surfaces composing the environment itself.
The ever changing Termina Field would have a large share of these puzzles. Actually fuck fields, have it be "Termina Expanse". A half-real between dimensions area that is a ghostly forest in some areas and other things elsewhere. An explanation for the opening events in MM.

In this game Fierce Diety is the antagonist. At the end of the events of MM, that Link took Fierce Diety's Mask back to Hyrule with him. Fierce Diety's Mask however, as the item description in MM tells you, is a Mask of different but equal evil to Majora. As Link returns to the world of Hyrule, reconnection to the Hyrulian godesses activates the Triforce of Courage in his hand. This makes it's existence known to FD who goes wild over lust for ToC. The Feirce Diety is a god of strife, domination, and conflict. Rather than care about the Triforce of Power at all, the thought of taking Courage and bending it and dominating the will of it's user is what FD lusts after. This is in service to better establishing what the ToC's powers actually are. MM link is taken completely of guard and falls into a chasm off Epona after the mind spliting headaches FD tied to his hip causes him. And so OoT/MM Link's life comes to an unceremonious end, at the bottom of a chasm FD beside him having nothing to possess. And so it sits, a Terminan god in a Hyrulian chasm, for hundreds of years.
Break to a new setting. Hundreds of years later in Hyrule castle town you start the game as an elderly Link, stern captain of the royal guard. Taking your patrol and performing your duties through town, your adjutant reports to you the King has summoned you for an update on the Yiga menace. Upon arrival you observe young Zelda bickering with her father. Zelda has garnered quite a reputation for herself and in a bad way. Rebellious, defiant, and extremely antagonistic to the crown. She seems to got it in her head that something is wrong with the very idea of royalty. Bookish that one, she prefers to sequester herself in her room reading massive piles of books, and resents being separated.
"Do not involve me in your political machinations father! It is no ones fault but your own the crown is swamped in so many corruption scandals! I will do my duty and accompany Link in the raid on that Yiga leaders stronghold an seal his evil with my Triforce, but nothing more!"
"Do not speak of such things in my presence Zelda!" bellowed the King. "I see you are as recalcitrant as ever daughter. Thinking yourself better than the crown while being part of it, such arrogance. You'll go to every village in the domain singing the praises of Monarchy if I desire it! Those damnable books have rotted your mind! How about I have half your books flung out the window if you cannot abide the orders of your king! Guard lock my daughter in her tower and make her watch as you do just that."
"You wouldn't dare!" Zelda shrieked as one of the guards dragged her down the upper hall.
"Sire you called?" says Link
[The above is meant to establish several things: Zelda is rebellious and hates the concept of royalty. The King is corrupt. And a Yiga menace is threatening Hyrule. This Yiga threat is lead by a young bandit named Ganondorf, who is yet another reincarnation of that ancient legend. The Triforce of Power has already awakened in him and he has been using it to wreak havoc. Zelda too has awakened her triforce early, easily in fact being quite a prodigy.
The King tells Link Ganondorf's lair has been found; a stone fortress cut into the face of the Great Chasm, which separtes Hyrule from the Great Expanse, an otherworldly tear in the very fabric of the world that  no one dare enter.
The game next takes Link to this fortress. After his force raids this fortress, Zelda reluctantly in tow, and after a short mini dungeon experience, ALREADY you start a final boss esque battle with Teen Ganondorf. The fight takes you to the bottom of the chasm in it's second phase and after being knocked back by one of the Ganondorf's attacks you land right on top of a pile of bones, a corpse. Right next to it is a mask. Inadvertently you place your hand on this mask trying to push yourself up. It affixes itself to Link's hand with a violent power and begins controling that arm. Link resists. Ganondorf oblivious to what's going on takes this opportunity to unleash an ToP powered attack at Link. The hurts Link badly enough that his will slips and allows the mask to use Link's arm to force the mask onto Link's face. An explosion of evil energy swirls around him and devastates Ganondorf. Zelda floats down from the fortress above with her power. She sees the scene and thinks Ganon has done something to Link so she tries to help Link with her power. The mask flings her aside in turn. However try as it might the mask cannot fully transform Link. This Link is experienced and his will strong. And the Mask learns an unfortunate truth; Link's soul is the hero soul and paired with the Triforce of Courage this makes him uncorruptible. This irks the mask. but it then also learns that the Triforces are not necessarily the same thing as the Hero soul, Demise Soul, and Goddess soul. (the full gravity of this only discovered in lore expositions later in the game)
Exerting the power it is able, it sends waves of it's dominating power upon the 3 wielders and "grasps" the triforces on each of their hands with it's power. Slowly it's power pulsates and the three there are wracked with headaches as an unnatural feeling takes over them. Like something is horribly wrong. Eventually Fierce Diety's power reaches it's climax and with one last effort the borders around each triforce crack and all 3 -rotate-. Wisdom goes to Link, Courage goes to Ganondorf, and Power goes to Zelda. As the change completes and the energies of each -lock- in place, the 3 weilders eyes flicker in a ghostly explosive energy and knocks them all out. Before the Mask can capitalize on this however Farore, Din, and Nayru IMMEDIATELY detect something strange and terrible has happened and descend on the scene violently. Without hesitation they take hold of the extra dimensional interloper and fling him back from whence he came, into the Expanse. They turn their attention on the 3 and realize they cannot undo what has been done. An evil wrought by a being equal to their power. And so the story begins.
The 3 are found, Ganondorf arrested, passive and lost in thought. And returned to the capital. None of them yet realize what has happened to them.
[This has all been to set up what is to follow. Link becomes bookish and reclusive. Ganondorf becomes confused and constantly absentminded in his cell. Zelda is affected most of all. Already rebellious her personality becomes positively explosive. She gets worse and worse until eventually she kills a bunch of nobles in a fit of rage and scars her fathers face. (And why is Zelda's mother never present in these stories? Fuck it lets write her in) The true nature of what happened to the 3 wielders is learned and Link is sent after Zelda. She has taken over the Yiga, seducing them with the Triforce of Power, and takes the name "Yig". She takes her new followers and embarks for Termina, after the power of Fierce Deity's Mask. She shows up as a reoccurring miniboss throughout the game. A counterpart to Sheik, Yig embodies a similar ninja theme but more physically heavy hitting. As a secondary arm she throws around a sickle on a chain and as a primary she equips herself with two sheild-guantlets, which she punches, bashes, and channels ToP spells with. In terms of aesthetics: think gesugao Zelda who infrequently dons a mask.
The King (and maybe Queen) orders Link to pursue Zelda in the goal of restoring the Triforces to their natural state, or failing that kill her. Ganondorf is then presented in such a way to convince the King, Link, even the viewer that the ToC has converted him to good. [spoiler]It is later revealed to not be true, as Ganon is still the Demise soul and this manifests in the ToC as a subversive, deceptive evil. One who is right at home among the corruption arround of this particular Crown. Likewise ToP Zelda is later redeemed.[/spoiler]
Ganondorf later follows Link into Termina, seeming the benevolent quest giver with a silver tongue and pechant for gathering information.
Before that happens however, the game starts Link heading into the expanse where he encounters a man with a collection or arcane Masks, who has been following him. I'd either make the original Happy Mask Salesman an ageless planeswalker type character or the one of his descendants. This individual tells Link that the expanse is a place where time does not flow (an excuse for the timelapse to come) and also senses Link's Triforce of Wisdom, and how unnaturally it rests on his arm. He tells him that Termina is a world of masks and that they hold greater power, and masks are optimal in this world as catalysts for his newfound affinity for spellcraft. The two convene at length and Link is furnished with some basic masks. Here I contrive some reason for this person to not be long for this world (illness perhaps)and Link utilizes his newfound inventiveness to create two things: the Face Sword, made by combining HMS's soul with Link's sword, and "Arcane Catalog" (more on that later). Link's new outfit has a wizard aesthetic to it. His green cap has a spindily-tipped Gandalf look to it. His talent with a sword is still operant however so while is outfit in large part is wizard esque, it's armored with leather in places, looking the part of a spellsword. Emphasis on the spell. Green and brown mostly but with accents of blue to visually indicate the presence of the Triforce of Wisdom.
With all the basic premises established, the introductory part of the game is ends, Link steps into Termina. and the game proper begins.


-----Further story/mechanical exposition------
Many unique masks different from MM (bringing back the old must-haves of course) Replacement for the Ocarina by having a legendary "Bard Mask" that you must acquire that you then place on your sword to gain the song making mechanic. Put it on Link to -learn- the various songs throughout the game. Put it on the sword to -play- the songs. The Transformation masks, of which there are 4 (+ Rito), will change the instrument depending on the race. I had a dilemma on what to do concerning the Face Sword on this, was unsure if I should allow the non human races to hold FS. I settled on making a Bard Mask dialog prompt for switches between the Transformation Masks, switching FS's instrument-form with it. Violin for Link, Drums for Deku, Guitar for Goron, Keyboard for Zora, Saxophone/other wind instrument for Rito. Concering equiping the transformation mask to Face Sword: Deku Whip, Goron Hammer, Zora Spear, Rito Fan. Whip has poison effects and grappling, the Hammer is explosive, Spear has water utility, and Fan has wind and sound.
Rito: can fly, but near omnipresent industructible sentry spirits will shoot you down, severly limiting where you can fly and ensuring you cannot have free reign of the entire world. Sentries can be obstructed from afar with a quick skill intensive setup but only temporarily. Necesitating mastering these setups in order to fly for longer. Some positions are simply unreachable by this setup and thus hold sway over areas that simply cannot ever be flown in, ever.

Another special-mask category; 'Summon Masks'. These masks summon the spirits of legends, automata, and creatures to use their abilities and as companions. The Horse Mask would be one. Midna's Fused Shadow another. Putting it on summons Imp Midna. Put it on the sword; True Midna. Or maybe rehashing an old character like this is dumb and a suite of original npcs will have to be written. Maybe even another Twili. Lot of potential for creativity there, Twili are cool.
Each summon character, lets use Midna[subject to change] as an example, would have two modes: contextual and companion (mask wielded and worn respectively). Imp Midna would do her action like doing a Twili spell then going away. Putting the Summon Mask on would bring True Midna for some constant support utility. Something of comparable simplicity as summoning a horse to ride.

I wasn't kidding with the /everything/ being a mask thing. Bomb Mask just up and replaces bombs. Instead, "bomb powders" are the limited resource here. Base, HE, Acid, Smoke, Flash, Implode, ect. Link can allow enemies to perform their grapple on him (being 'eaten' counts) and detonate worn Bomb Mask while it happens for x4 damage. Weild-bombs are not held and thrown overhead as is traditional but instead nestled in a cradle on a stick and -flung- or -lobbed- at a target. This is done for accuracy and comfort-of-control.
'Archer's Mask' even replaces the bow. Base arrows return as the sole resource and Arrow Crystals must be collected for elemental arrows. Magic Meter returns as well. (Stamina does not.) Arrows also have an alternative use to their direct-use counterpart.
>Base arrow
Now all elements have a corresponding "torch" that can "light" a base arrow with a low power version of their effect.
>Fire arrows
Instead of a whole separate bomb arrow you instead have fire arrow combine with your/the environment's bombs for a fire-arrow-boosted explosion.
>Ice arrow
You know how shooting through an already existing flame lights a regular arrow on fire? What if it was so that the only two arrows that are affected by being shot through a torch are regular and ICE? When shot through a torch Ice arrows generate water, lots of it. Water  Buoyancy puzzles and shorting out electronics and shit from there.
>Electric arrow
Shoot one straight into the sky at a designated "thunder cloud" then it'd be gone. You then take out your sword and whatever you target and swing AT a thunderbolt would strike it. For puzzles you could have some targets that can't be shot directly with Electric arrow and only from above, which you have no line-of-sight to. This is solved with the lightning strike special.
>Dark arrow
Gravity effects when shot at special symbols strewn about the overworld and it's debut dungeon.
>Light arrow
? Unsure. All I can come up with are things too-close to direct firing's effect at the moment

List of other mechanics:
-Sheild surf with surf-sail + Rito Fan = a better Sand Seal. For use on sand and snow. Maybe water too until Zora mask renders it obsolete.
-Concerning Deku and Rito: Deku "Scrubs" aren't cool enough so I want a better implementation of the plant-race, taller perhaps. Rito cannot truly fly (TOO much freedom design wise) and need updrafts and windstreams in the sky to rise. Link can use Rito fan to make a *slight* diagonal updraft for takeoffs, then quickly transform into Rito to use it.
-There is an in-universe explanation for the concept of the inventory in this game; "Arcane Catalog". Using the ToW as a base for the concept, Link devises a way to conveniently store and rapid-use the catalysts (Masks) he will come to collect. Part of the inventory is displayed in 3d space with grids (and/or an item wheel) of magic circles containing a given inventory item.
-Dodge-slowdown reequip: I repurpose botw's flurry rush to instead grant reequip opportunities.
-Dodging of enemy attacks and environment hazards must be managed carefully to always have fast-equiping available
-Terminology: Fast-equip & Hard-equip. Hard-equiping stops Link until he pulls the mask/item out of Catalog and equips it. Ragdolls if enemy/hazard hits
-Terminology: Masks are "wear/worn" or "weild/weilded" ie: "on next ledge, wear-bomb the rock", "above the wall I weild-bombed left target"

Questions that need to be answered:
?How does FD Mask go from MMLink's possession to gaining the agency to antagonize Termina and the characters
?How to establish Triforce-of-Courage-Ganondorf
?How to start immediate Ganon fight
!?Ganon arrested, redeems and becomes politically trusted
?Zelda evil or merely anarchistic and Ganon good or actually subversive
!Ganon's evil may eventually become apparent but ultimately inconsequential
?How to introduce Old Link
?How to introduce Face Sword
?What ARE the ToC's powers
!!FD=competitive god of conflict and victory
!!"Could this mask's dark powers be as bad as Majora?"
!!FD tries to rotate again, ToC his fav, wants it on corrupt Zelda. Majora wants ToP on Link. Worst possible outcome.
?Majora should then, necessarily, not be acquired upon all masks collected but rather mid-late game