Probably not.
There isnt any critical fights, really.
There's different mechanics that you can completely avoid (Landslide) Or for Twintania, kill snakes, to debuff asclepius and burn it. Stand in neural link, to take reduced damage from Aetherial Profusion/Hatches.
War is DPS type tank.
And BLM has manawall, that can completely block 2 attacks, mana ward can reduce damage of stuff, by quite a lot, and apocathesis that increase resistance. None of them are necessary for anything.
They removed archer skills from DRG cross-class, so we can't use straight shot, raging strike, cause they made DRG rather OP...so...i doubt they will add other cross-class buffs, that will make you OP again.
Tanks don't need more defensive skills, unless you want the game to get even easier than it is. Ofc more defensive skills wouldn't save you from Twisters or blighted, though.