-FULL JOB CHANGES:


NIN:

Huge changes on Ninjutsu and Mudra, and they are now categorized as GCD actions (with charge actions up to 2 stacks)
Almost all actions have their potencies adjusted
The play feel itself however doesn't change
NIN DoT is no longer a combo action, and is now a singular action on its own
Kassatsu has been reverted back as a normal ability
The specification of Ten Chi Jin are now interchangeable actions and can activate Ninjutsu at will * Trick Attack's duration has been increased, but its effect nerfed. TA can also be applied at any directions instead of strictly from the back (It's meant to have its usability changed to be easier to use, but with the effect nerfed to compensate)
Hellfrog Medium, Bhavacakra, Bunshin's gauge consumption is adjusted from 80, down to 50. In according to this change, the overall skills will see a review in its Ninki accumulation.
SAM:

SAM's overall DPS will see increase compared to 5.08, but if you judge it based on patch notes itself, it may be taken as if it's weaker, instead of stronger.
Shoha' potency is fixed at 400. It will be incorporated as part of your rotation, and you are required a medication stacks of 3 to execute it (In Japanese, it'll have a new stack name called Kenatsu （剣圧, Sword Preasure/Aura, which is basically your medication stacks)
Meditation stack is granted through Meditate, Iajutsus, and Tsubamegaeshi.
Dev team made estimations that that you may be ussing Shoha once every 40 seconds.
The cooldown after using Tsubamegaeshi will be affected by Skill speed
Usability of the job will increase for the better.
Summoner:

Egi Assault 1 and 2 are now categorized as spells and will be affected by GCD. Due to this change, action potencies will be increased.
SMN's overall firepower will be increased.
Your opener will see yourself pressing up to 6 buttons lesser at the first minute.
Overall action recast (cooldowns) will be adjusted to make it align nicely.
Ruination effect from Tri Disaster deleted, what replaces the effect will be direct damage.
Bane's trait will be adjusted, where it's additional effect is adjusted from 15% to 100%
BRD:

BRD won't be like what BRD was during 4.x but song will now have support effects added
The job overall will be buffed including its support ability
While having synergy, but it will have its firepower weaker than MCH as a result.
The sound effect for Apex Arrow when it's accumulated will change
MCH, DNC:

Potencies increased. Potency increase will mean overall firepower increase.
Some skill will also see recast timer shortened.
MNK:

MNK's firepower will retain.
Mantra is too strong and therefore it will have slight adjustments
DRG:

DRG's firepower increase
Usability will be improved
RDM:

RDM's overall potency will increase and buffed, at a considerable amount.
RDM's trait will also be buffed as well
Devs do acknowledged that the proc is very RNG reliant, therefore Acceleration's specifications will be changed to have up to 3 stacks, and the timer eliminated. However its cooldown will be adjusted as a result.
BLM:

BLM will see no changes.
Minor improvement on displaying your Triplecast stacks, that's it.
SCH:

Improvements on usability
WHM:

Effect range for Asylum will be adjusted
AST:

MP consumption for spells will be adjusted
Potencies are being adjusted as well - Regarding cards, Minor Arcana will be adjusted so that it reduces unnecessary steps. One such example would be how it will directly apply Lord/Lady instead of making the card into Lord/Lady and then you use it
Specifics of Collective Unconscious will be changed where executing the skill will bring different effects depending on whether you're in Diurnal (HoT and defense barrier of 10% damage mitigation) and Nocturnal (Instantly grant 10% damage mitigation shield that lasts 20 seconds) will be different depending on which sect you're in
Tanks:

Buffs in defense
Reprisal is now an AoE effect instead of a single enemy, and duration buffed to 10 seconds.
Sentinel, Vengence effect will last 15 seconds
Holmgang's effect timer will also be extended.