A blaster and my scrapper can take down Dr. Vahz and a couple minions in a difficult fight. But twice we are defeated by a group of grey and green con R. Invaders... That doesn't seem balanced to me.
I think the problem is with status effects and how easily they land, even if the user is well below your level. Also, mobs using status effects are not losing an appropriate amount of Endurance. A hero can not repeat-use such powers without losing a very significant amount of END.