Well she IS pretty overpowered by nature of her abilities. Rez is just absolutely nuts in any game like this, and at the end of the day, despite her lacking offense and minimal survival capabilities, she does have enough, that with proper coordination and a little positioning, she can be outrageously overwhelming in a game.
That being said, if a DPS does manage to find her in a bad spot, and can't almost instantly kill her, they're probably doing something wrong.