Which is how healing on smn and rdm feels. Even if they had the mana to sustain doing it for a long time, it would be super boring. I don't expect healing on those classes to be interesting, much like how I don't expect dpsing on a healer to be interesting.
However I do note the difference that the opportunity for healers to dps does arise all the time, unlike healing as a rdm or smn. I am merely pointing out how things look when you flip the argument on to dps classes with healing built in.
This would only work if casting support abilities wouldn't break the combo, and if the period in which you have time to finish the combo is fairly long to allow for periods of time when the healer must heal a lot, otherwise it would feel punishing to play your main role and that is not a good thing. If all this was the case I would welcome something like your suggestion.
I feel that to go as far as giving healers major dps cds for personal burst similar to the other roles would be going into the realms of becoming a hybrid. Which would be OP. It would be fun, but I don't see it happening
