We didn't need healers before and a pure 100% DPS group is lacking something to make them even stronger. If just one of them equipped something like Spell Power Cure or Olorime they could increase the group DPS exponentially even if they didn't do dedicated healing. Typically what I see in such groups is someone doing exactly that (And it's usually me).
The Ring can make it a possibility, but it still won't stop one shots from bosses. This is why some groups do 1 tank, 3 DD's as the tank keeps the crowd in check and the boss on them while the DD's go to town killing everything.