I pride myself on being a true hybrid. Tell me which of the 4 druid roles you want me as with enough notice (or which 2, provided you pick 1 feral and 1 caster spec), and I'll perform them as best I can.
That said, Bear tanking is my main spec, and so unless something goes wrong, that's what I do. So far in firelands, I've had the luxury of tanking my ass off, but that came to an abrupt halt recently.
I run with the same 3 healers every week, with no healer subs. Over the weekend my Holy Priest had some RL stuff come up that took them out of action for a few days, and my Holy Pally is unavailable this coming Wednesday. Luckily, this happened as my 3rd tank came out of a break, so I quickly called on both tanks, and promptly respecced resto.
Now, most healers are able to warm up on earlier bosses. Shannox, Beth'tilac... that kinda thing. Haha no such luck. Direct to rag we go 0.o
So after some paniced reading through Lissana's healing guides, most of which I'd already read some time ago, and some careful reforging to the 1573 haste threshold (and strict orders to my warlock to keep Dark Intent on me), I stepped into Firelands.
Now, I healed some T11 fights, most notably Al'Akir, where I performed really well, so I'm confident of my healing ability. I'm just nervous going against our healing heavyweights, with their tier bonuses and weeks of experience in this content.
Thankfully, I'm a Druid, not one of those healing classes that have been broken and re-broken in an attempt to get them balanced for PvP (side note : I recently read that the reason Shammies are still underpowered is because of PvP - GG). Druids are most definitely overpowered at the moment, and it shows. I topped meters on every single Rag attempt while not being 100% sure what I was doing at times. After having a look at firelands rankings, not just for Rag, but all bosses, it's clear that druids are just completely overpowering the other healing classes.
The biggest problem I had was mana. I had to regularly hold back in order to prevent myself from going oom. Coming out of a P2 stack-up (to handle seed explosions) I often found myself looking at a "Low Mana" warning, with no time for a concentration pot, and my innervate CD giving me look that said "haha not gonna happen".
This was made even worse if I died and got a combat res from the lock or the dk. Since they don't have an awesome glyph like druids (blizz, seriously, please fix this), I came back at 25%, and had to find a way to regen mana faster than I spent it. I found myself keeping up a 3 stack lifebloom on the tank, and only using a rejuv or a nourish if someone dropped under 60%. I felt a bit like I was leeching mana from the other healers, but so be it.
The other problem I had was trusting the other healers. Not that I didn't trust them to do their job. Hell, the one is my wife, and the other is a very close RL friend. The issue was more that if the entire raid was on 100% except for one person, I felt like it was my job to rejuv them to get them up, not realising that the other two were charging a Holy Light and Healing Wave as I did so. Learning to know when to step in, and when to back off, was the biggest lesson of the whole exercise. In the end the pally focused the one tank (including his Beacon of Light), while I kept Lifebloom ticking on the other. Even when not tanking, the stacking debuff on tanks can tick for a fair amount, so this system really helped to keep both tanks stable.
Ultimately, a druid has some amazing tools for this fight. When the aoe hits, a well timed WG ticks for a ton. Aiming an effl correctly while stacked will also do the trick, and more importantly, as it's now a smart heal, will save those who otherwise would have died (in the end, of course, this matters FAR more than meters). Convince your two tanks to stay close to each other, and Effl will tick on the two of them almost constantly.
One complaint I have is about Nature's Swiftness. Activate it, and HT is an instant, right? So why is it that I get the "you cannot do that while moving" error? I often found myself looking at a tank on 10% health, while we were all rushing to stack up before seeds explode. I had to stop for a split second, make sure the heal went off, then keep running. This seems like a bug to me.
I must say, I'm loving the Resto setup at the moment. I've been tempted before to change my main spec. It's just too bad that both Bear and Resto are so incredibly overpowered at the moment. I guess I can't do both at once :) I'm looking forward to seeing how I perform on our farm bosses, and actually downing something for once. All those Rag attempts, while a fun learning curve, definitely take it out of you.