I think I'm in that camp. Non-healer healing should either have; a hefty cooldown (90s+), or come with damage costs (putting it on the GCD, having it spend a resource that would otherwise go to a damage ability, etc.). Exceptions can exist of course, but in general I think these are suitable rules. The healing should also be relatively low in potency so that it's only good for some sustain, not enough to fully rely on for long periods.
