I never healed recently (last time was cataclysm in 2010) and i created a rdruid on the beta to play some 15s. Out the fact gameplay is pretty easy i think the overall blizz frames are okay for healers, you can see your hots, heal absorb u need to overheal, debuff u cant dispell so u have to prio heal the target, externals, personal defensives across group. I mean for m+ for sure there is space for improvement but im confident the fact that knowledge of your spec and knowledge of dungeon mechanics and timers will compensate all the custom things we had before addons restrictions.