Actually, no. You can handle every floor without a dedicated healer just fine. You simply need to be careful and know when to exploit your self heals. Paladins can also serve a pseudo-healer if needed and we all know Warrior is just stupid with all its self-healing. Would the necessary coordination work in duty finder though? Probably not. At the same time, who cares? If you don't want to risk a bad group, you can still go in with a premade.
