Balance is pretty good, but that is because the job identity is practically non-existent among some roles. Tanks are my my favorite and having them all at 90, they are 93% the same with a few minor quirks. The particles they poop out is the biggest difference between them.

I feel like the problem is the game is designed around the 120 second burst rule, and every fight is just a DPS check with an enrage timer. Healing and tanking are braindead and everyone's main role is to meet the DPS check. It's to late for this to change now really, but hopefully when we get a 3rd final fantasy online it will be built from the ground up to be more engaging and varied.