Why does KRU take reduced damage from percentage health effects?

KRU heals plenty already and his reduced damage from percentage attacks makes him a viable tank against Vader and many others. Once geared up enough he's nearly immortal as long as he doesn't get certain debuffs. I've had many a territory battle where the whole team is wiped but KRU keeps plugging along. Even put it on auto for 30 minutes to see if they could eventually wear him down but it was a stalemate.

In short making him more like kylo would not help him be a better tank and would be unoriginal.