So I took the opportunity my first evening playing after the patch to try out as many toons/specs as I could, just to get a basic idea in my head so I could give it some thought offline. I tried druid healing and tanking, then hunter and shaman DPS.
The highlight of my evening was by far the druid healing. The basic mechanics of resto druids didn't change all that much. Pretty much the only thing I found myself keeping in mind was that lifebloom was for a single target. I've been thinking of macroing that to cast on a focus target since I do tend to accidentally flip it to other people and end up having to put it back. I haven't even tried yet because I don't think they've fixed the issue with these situationally different abilities with the same name and how they behave, or more accurately don't behave, in macros.
The first thing I noticed healing was there is about twice as much damage to heal. A little less than twice, but pretty close. Before the patch I amused myself as a healer by seeing how much damage I could do while still keeping up with the heals. In ICC gear that pretty much meant I was DPSing just ever so slightly more than I was healing. I did not have the opportunity to DPS more than twice in the heroic I healed. Kind of ironic considering the DPS talent I took to do a little DPS while healing. I'm still going to keep that a while and hope that changes.
I think they hit tree form dead on as a cooldown. I used it a couple times when the damage was a little heavier and it felt very smooth. Although I think the new tree models that were leaked look like butt, and not the cute furry bear kind.
Efflorescence was better than I expected after watching it get nerfed to the ground on the PTR then buffed back up again. I had forgotten it had switched to swiftmend though so I was spamming regrowth trying to see it till I gave up and reread the talent.
All in all my playstyle of favoring instant over anything with a cast time still works just as well as it ever did if not better. I did find myself using nourish a few times that I wouldn't have previously, but I never did find a niche for regrowth or healing touch.
Nature's swiftness has definitely outlived its usefulness, I didn't spec for it and I doubt I'll ever miss it. I used it very rarely before and now that heals are smaller and the cooldown remains unchanged it just isn't worth it when there are other talents I prefer.
Next thing I tried was tanking and it was painful. I figured like healing before it there wouldn't be that big of a change, I was so wrong. Of course I knew that our AOE was on a 6 second cooldown and rage had been normalized, but oh my god it was... pain! I had doubts of my desire to tank in the first time, well ever. It got better as I went along, and never was I doing a poor job, it just wasn't very fun. I think I pressed maul maybe twice the whole instance. Not because I was rage starved, but because I was too busy playing musical targets compensating for the lack of swipe that I really didn't have the opportunity to watch my rage bar and tank. I never had to look at my rage bar before except a passing glance just before a pull.
In general I found myself with just way too much to look for. Heaven forbid someone not talent for faerie fire applying 3 stacks at once. Having tanked on everything but a warrior before the patch I'd say the druid just got harder than a pre-patch DK. Death knights also suffered from too much to watch syndrome, but it was easy to fall into a pattern with some practice, I am hoping the same will be true for the new bear changes. I'll definitely have to try out tanking on my other alts as well once I get my druid down. One thing I learned playing with 4 specs in one night is stick with one or two before branching out.
I'd have to say my second favorite after healing on my druid was DPSing on my hunter. I'm still a ways away from getting the pattern down, but for the most part the marksman hunter feel was there. Really nothing of note to report, I was performing about the same as I was before the patch. A little lower, but I really wasn't using my cooldowns as much while I was getting the feel of the new focus system. Probably more importantly I wasn't using anything near an optimal rotation.
Then I logged off for the night on a rather sour note after DPSing one last heroic on my shaman. For the first 4 pulls I was simultaneously updating my bars and speccing as I was expecting to heal. Once I had all that taken care of I noticed that I was doing really low damage, half what I would have expected. Taking into account that I didn't get a chance to train first I was missing out on 20% nature damage and 5% agility from masteries, but that wouldn't explain such a radical drop.
The other thing that I was playing with was when to use the single target vs multi target fire totem and a single lightning bolt vs chain lightening. Before the patch it was a no brainer and the multi target spells were better even on single targets. Being more conscientious of which abilities I was using got me probably 500 more DPS, but I was still 2-3k off from where I'd of expected. I'll definitely give it another shot once I have a better handle on my primary specs for my raiding toons.