My primary concern as i've stated earlier is that they've forfeited DPS in exchange for party/raid heals and utility, which again has come at the cost of their own self-sustainability.
A comparison of a Ret Paladin's self healing ( ~20k Mana for a ~30k heal) compared to a Elemental Shaman's/Shadow Priest's self healing is pretty self-evident. All three of those are hybrids and i've listed only three of several.