So let me tell you what my experience has been like.
After raiding Tuesday with the crew, the content felt a little disheartening. During Beth'tilac, we had a player miss a Power Word: Barrier and still got through it with barely a scratch. We normally run six healers. But just for kicks, we decided to run five healers on a few of the bosses, and we barely noticed anything. Traditionally, we've always cycled through our tools to help us for progression, and it sure as hell isn't necessary anymore. I had several healers who decided to contribute a little additional DPS. Resto druids weren't using their Innervates or Tranquility as much. Shaman? It almost seemed like more Lightning Bolts flew out than Chain Heal.
Ragnaros still presented a mild challenge, but that was largely due to the other stuff that players needed to do. There were no major healing targets to go after. The highlight healing points would have been during seed phases when we all had to stack up and heal through the different elementals and adds streaming in. Meteors during the final phase were much more forgiving.
Don't be alarmed if the net HPS for healers is down. I've seen some complaints about healers with normally high HPS who have plummeted on the meters. But that's a product of any kind of damage nerf. If there is reduced damage going out, then there isn't going to be any healing going out because it simply isn't required.
All this stuff about staying out of fires and such just seems so inconsequential now. Not only does it feel infinitely easier to avoid them now, but even if you do get hit by them, you can afford to make the additional mistakes anyway.
Ways to make Firelands challenging for healing again
Not exactly something you want to really encourage in the long run, but maybe it'll keep your healers fresh on their toes.
Drop healers or have them switch roles. Easiest way out for you. Not a bad time to get a healer to switch to a DPS spec. Raids will go more quickly and the healers can feel active again. If they don't have alternate specs, I'm sure they'd appreciate the day off, and you can then pick DPS players to come in. Great time to trial new players for the upcoming tier 13 stuff, as well.
Reduce cooldown usage. Do you schedule or preplan defensive spells? If you're going to drop healers, you may as well consider dropping a cooldown or two from any rotations. I'd consider doing this for farm, though. If you're on progression bosses still, retain your full arsenal.
Push boss stacks. Any kind of mechanic where bosses continually get stronger over a period of time (for example, Majordomo Adrenaline stacks) can be extended. Consider letting them go a stack or two higher than normal. Keep pushing the limits as much as possible and see how far your raid can punish themselves.
Achieve achievements! Everyone loves achievements! One of the crafty players in the guild who does the driving on Lord Rhyolith sneakily kept telling players to target one specific leg, resulting in the achievement for Not an Ambi-Turner. Great time to shoot for an achievement mount run!
Don't be discouraged
Don't be depressed about healing right now. Yes, it's easy. Yes, it's not remotely challenging anymore. Just hang in there and wait until tier 13. Start getting involved with the heroic modes to at least try to keep your edge. Your guild may give you some flack about your healing numbers and why they're low. You need to explain to them why that's the case. Tier 13 is coming soon!
When I'm explaining this stuff, I tell them that overall HPS is going to be based on player performance. If players are doing a great job avoiding stuff as it is, then the raid group isn't really going to need the healing numbers from before. Just make sure you don't tell them they can stand in bad stuff or get hit by them. They've developed some positive habits. Keep reinforcing it so that your raid group will be in a solid position to challenge Deathwing.
How has the Firelands nerf affected you? How has it affected your guild and raid? Are you relieved in the sense that the progression roadblock isn't there anymore?
Need advice on working with the healers in your guild? Raid Rx has you covered. Send your questions about raid healing to firstname.lastname@example.org. For less healer-centric raiding advice, visit Ready Check for advanced tactics and advice for the endgame raider.