I have defeated the bosses on the Asian version alone, but had to get the enchanted gear with some daily bonuses.
Some 3 or 4 are hard and can take more than 40 minutes. And remap your LB button to something less used. LB default is changing a tab, it's stupid.
RT doesn't need to be attack, it's not a shooting game.
Change the spell tabs alternation to RT and LT, just like Final Fantasy XI did in 2006...