Hardest thing for me about T5 has nothing to do with the mechanics, but that the red triangle icon over-characters-heads for fireball blends into both the background and the spell animations for black mages and scholars / summoners. If the person isn't standing directly next to me I can't see it, which makes the "offtank run back and forth" strategy pretty tough because even with all spell animations and names turned off, the triangle just isn't big enough.

Really now, a red triangle? When there is already so much red in the dungeon?