One of the interest part of the game is to think how to form a powerful team. Tanking is one of the important consideration somehow.
I suggest that there is a function to select the "flight level" of the character.
For example, I have 5*Kitty card at level 462. I can select its “flight level”, ranged from 255 to 462. I will put my Kitty at around level 400 so as to keep her behind DD and BRB.
The game will be more interesting with this function.