If healers don't get any new buttons to press, I've always liked the idea of giving healers a core mechanic wherein their main offensive GCD will have an increased potency (of up to 30 or 50%) which gets dropped if a healing spell is cast (similar to Monk with their GL stacks disappearing after Tornado Kick).

This will then give them a bit more of a kick, strategy, planning, choices (ie should you get someone healed at 40% or 30% in order to get that last spell in or something) and hopefully give people who make bad choices a bit of a kick up the rear to get better.

As for someone telling you what to do and what not to do in dungeons, the classic "you don't pay my sub" should suffice. Advice is cool, orders are not.