Basically title sums it up. Unsure if this has been brought up before, unable to search accurately from my little phone.

We all like the ability of the heroes, why not tweak it bit more for during the defense? Have the heroes automatically switch their ability on when their hp lowered below 65% or something in that area. I mean if they are going to perish and die in honor of protecting the castle why not let them use all their ability to the fullest =)

Think they will become more pivotal in clashes than having them silly walking back and forth.