Which end game content are you referring to.

To be fair, it sounds like the issue was related to 2x AST, which is hard to learn in basic dungeons where there is only 1 healer. Did you bring any of this up with them during the run?

Also, afaik, AST Sect that gives regen is generally considered better than shields - no? In this case, don't the regens stack like Medica II/Regen?