Originally Posted by Zandel

My question is this:

At what point is High Atk / High Def better then that extra hp in actual combat?
Or in other words, which girls with lower hp do you find worth using in your squads even tho they lower the total power of the squad?

You solve the problem by having the deepest bench of anyone. That way, no matter the map, or situation, you can always form the right team for the specific problem you want to solve. Just having the best 20 characters is meaningless in this game.