If they want to make healers engaging, they can just add a system of short (but highly effective) buffs for you to cleverly weave in between your heals depending on the situation. Some healers in DAoC had a blade-turn buff that worked as a protective bubble that fully absorbed the next hit, regardless of how much damage it would have done. The Warden class was a fairly weak warrior, but it had a pulsing version of the spell that just ran idly in the background, ticking every six seconds at its highest level. That shit was awesome.

Having some sort of damage is obviously needed to level a healer while questing and such, but I'm with you in not wanting to fucking DPS while healing. Had zero interest in healers in FFXIV for this exact reason. Let me focus on heals while occasionally dropping a quick damage buff on the DPS, a shield or blade-turn on the tank, and maybe a pass mana regen on myself or the mages.