Hmm hope i understood you correct for. All ingame group instances are already capable for what you are saying . For instance - Healer is tanking on the last boss.
With the way how sets, chamipion points and classes are spec'ed out, is there any chance we can get new group content that does not require the traditional roles?
Most players can self heal, deal damage, mitigate damage and sustain. I would like to see some group content that is geared for a all around player experience.