They got healing bad since the beggining and this is just a consecuence of it.

They are attemping to fix healing taking the easy routte- making the healer job weaker instead of giving a revisit to most encounters in this game to add heavier damage income to tanks and the party from random/unavoidable sources. Okay, reworking the whole game is too much? make it past level 50-60-70 and start giving healers spells to deal with that after those levels.

Force the healers to heal. Give them a bigger/varied healing kit - Earthly Star and Synergy from AST or Excogitation from SCH are a good example of interesting healing spells. Other MMOs have delayed heals, HoT healings, chain heals, heals that react to damage...

Just stop giving healers straight heals, specially if they are oGCD. That takes us nowhere and do nothing except for making the situation even worse.