Most of these have been unresolved for more than a year since closed beta....

In no particular order :

-Lag compensation is either not in the game, or does not work properly. Try hitting fast mechs with a 300+ ping. With missles/ballistics in particular. Status : ???

-Matchmaking is still pitting teams of premades against randoms, with wildly varying skill levels and tonnage distributions. A large number of games end in very lopsided wins, where the majority of the losing team deals less than 100 damage. Status : ???

-Hitboxes/hit registration is very wonky, with many cases of mechs not taking damage despite being stationery. Most famously for spiders. Status : Currently being investigated.

-Weapon balance is in a terrible state, for more than a year the metagame has favored high damage, pinpoint weapons such as PPCs and loadouts focusing on long range, high damage alphas. The majority of the weapons in the game have little to no usefulness. Status : ???

Pulse lasers are inferior to standard lasers in almost every way.

Large lasers have no use compared to PPCs, considering that one is a instant fire weapon and the other is a beam.

Flamers/MGs, self explanatory.

Gauss rifles charging did not discourage the prevalance of gauss boats sniping, it just forced them to snipe more. Which was never hard on maps like desert.

Heat dissipation renders energy weapons a liability in a stand up fight, whereas ACs can fire pretty much forever.

SRMs scatter too much and serve no purpose when you can alpha with PPCs/ACs/Gauss instead. Even with artemis, they have massive spread at 200m.

ER weapons have no use given that all weapons have MASSIVE max ranges compared to their TT values.

LRMs/Streaks are only useful when mounted on a mech with ECM/BAP or playing in a premade with a ECM mech. In a pug match, the prevalance of ECM, which takes absolutely zero skills to use since it is a passive module, renders these weapons impotent....and you cannot always count on a friendly counter-ECM to be available. Also, missles serve no point when you can just do a 30-40 damage alpha to the CT instead. LRMs are also easily neutralized by AMS.

Artemis usefulness is questionable given that having LOS means getting cored by PPC/Gauss/ACs, and it seems to have neglible effect on SRMs.

LB-10X is inferior to the AC10 because it cannot do pinpoint damage.

Chainfiring AC2s and 5s can render a target unable to fire back due to cockpit shake. Being unable to fight back is NOT a good thing and just frustrates people.

Ultra AC5s jam so much that they often leave you defenceless infront of an enemy. Also do not fit into the metagame of massive alphas.

-Poptarting is still very easy to do, especially as you only need one jump jet. Additional jump jets are un-necessary, even for light mechs that are mounting it for mobility Status : ???

-Mech balance is terribly bad, with some variants being blatantly better than others, especially for hero mechs. This is largely due to PGI's insistence of putting multiple ballistic slots in a location, see : dragon vs hero dragon variants, or boars head vs AS7-D. Some mechs are a complete joke and nobody uses them seriously anymore (see : Centurion). The limited amount of missle tubes on some mechs also makes LRMs easier to shoot down with AMS, or harder to aim with SRMs, which makes mounting missles on certain mechs or variants a stupid move. Status : ???

-Some maps are terribly designed, nobody enjoys 5 mins of walking before you encounter the enemy, see : the stupid artic mountain map, where the best way to win is to avoid the enemy and have as many lights as possible run in circles to cap. Some maps are also weighted more than others, and will show up more often. Forest colony, one of the most well designed maps in the game, almost never shows up in the queue now. Status : May possibly be improved in the latest patch due to new spawn locations.

-There is no way to scroll up for the chat log. Status : ???

-There is no way to test new loadouts before being forced to pay the customization fees, resulting in potentially a LOT of wasted money to find out that a load out does not work well. Status : ???

-The economy results in tons of wasted mech xp that do nothing, as well as being forced to grind hundreds of games to get 3 mechs + elite efficiencies, of which two mechs most players won't use anyway. This has turned a lot of people off from the game and from trying out different mechs and variants. Status : ???

-There is no reason to use ferro fibrous armor over endo steel given that they occupy the same amount of slots, but endo steel gives much more tonnage for nearly the same amount of c-bills. A simple fix would be to make FF armor take slightly less slots, but PGI shows no sign of looking at this. Status : ???

-There is no reason, ever, to use single over double heatsinks. Status : ???

-Given how powerful ECM is, there is no reason not to use a ECM mech whenever possible. This mainly applies to light mechs. Status : ???

-The critical hit system makes no sense when you can just skip critical hits and core a mech in the next alpha anyway. It would only make sense if internals had equal or more HP than armor, which would encourage the use of critical hits to disable equipment, rather than just blowing the entire section away through sheer damage. Status : ???

-There is no reason to use CASE when you can mount ammo in the cockpit and legs. There is also no reason to use CASE on a mech with a XL engine. Status : ???

-NARC/TAGs are largely pointless. The latter -may- be useful in an organized match though. Status : ???

-Weight class matching fails to take into account that mechs at different ends of a weight class are not balanced with each other. A locust is in no way a fair match for a ECM raven or spider, or a jenner, just as how a dragon is in no way a match for a orion. Status : ???

-Fast mechs do not work for mediums/heavies due to their large hitboxes. It works well on lights because they are small, but when people used to run a lot of fast hunchbacks/centurions, they were still extremly easy to hit due to their relatively large models. Mediums and fast heavies (60 tons, like the dragon) are in a tough spot because they were designed to have speed grant them survivability in the TT, which translates to zero survivability in MWO. Exception : If the player shooting at you has 300+ ms ping, then you are nearly invulnerable. Status : ???

-Ghost heat does not actually prevent people from boating weapons that were never meant to be boated, such as dual AC20 jagermechs. All they have to do is chainfire, which completely bypasses the ghost heat mechanic, and doesn't actually reduce their insane damage in any way other than to make it (slightly) harder to move out of cover, fire, and reverse. Status : ???

-You cannot bring up the tactical map while spectating. Status : ???

-Ballistic hits cover your cockpit with black smoke even if they hit nowhere near your cockpit. Status : ???

-Kill/Death messages dissapear from the chatlog after your death. Status : ???

-You cannot type while the tactical map is open. Status : ???