If the devs continue on this path of putting more and more powerful heals on tanks then they should go all the way and reduce from a trinity to a duality of just dps and tanks. This half hearted approach is the worst of both worlds. Healers are less and less needed for their healing but their damage aspect is mindnumbingly boring. Job design in pvp is much more coherent in what it is trying to achieve and it has dialed back the trinity immensely.
I think SE needs to decide on one approach. Embrace the trinity and dial tank sustain back massively or embrace pvp logic and make every job a dps with different extras and built in healing. Both are valid approaches, this current middle path pve job design is on is not.