Don't worry, I'm not considering switching mains, even if my initial impressions of the changes to holy priests were a bit of a mixed bag. However, I think the hierarchy of my alts might change significantly, because I suddenly find myself wanting to play my hunter again, without a doubt the level eighty alt that got the least playtime this expansion.
But let's start at the beginning: My hunter was actually my very first Horde character, and my second Hordie to reach the level cap at seventy. She never came close to threatening my priest's status as my main, but as far as alts go she was very fun to play. There were basically three things that I really liked about huntering:
First off, the pets. While the Beast Master spec never appealed to me (I started levelling as Marksman in late Vanilla and stayed loyal to it until WOTLK), I still loved the hunter's ability to tame lots of different animals and the micromanagement they required. I remember running all over the world, taming seemingly random beasts just to learn the next rank of Bite or whatever. I remember levelling with two pets at once, back before they auto-adjusted to your level and took huge amounts of XP to level up, when it was very much not recommended to have more than one pet while levelling. I remember keeping several stacks of "pet food" in my bags, because not all of my pets liked to eat the same things. I remember the art of keeping an eye on my pet during boss fights, calling it back and casting Mend Pet at the appropriate times to prevent it from dying. As Marksman spec it didn't exactly make a massive contribution to my damage, but I still prided myself in taking good care of it.
Secondly, I liked the way Marksman hunters did damage. (Beast Masters had the reputation of being one-button spammers at the time, but they weren't the only ones.) It wasn't hugely complex, but it did require a minimum amount of attention and not clipping your auto-shots was a bit of an art back then, before Blizzard changed it so that this couldn't happen anymore.
And finally, I liked the hunter's utility. I've always been a group player and was never the most attracted to the classes and specs that could pwn on their own, but instead loved those that could bring something to a group that would really make a difference. Misdirection was a unique skill at level seventy, and with threat still being a genuine concern, tanks really appreciated the extra boost. On some fights it was even preferable to have the hunter pull for the tank that way.
And the traps, oh the traps! They were an amazingly good form of crowd control, seeing how you could trap almost anything but the occasional water elemental, and you could refresh it too! At the same time they had a reputation for being a bit unreliable due to inexperienced hunters frequently breaking their own traps and causing hijinks. But I had become quite good with practice and people were always impressed by my trapping. It was engaging and fun.
When WOTLK came out, I switched to Survival spec because my formerly shadowy priest had gone holy, and I liked the idea of my hunter becoming the mana battery instead. It was fun at first, but over the course of several months it turned out that a lot of the things that I had enjoyed the most about huntering had been more or less completely eroded.
I don't want to bemoan the fact that pets have become more convenient to keep, but in all honesty... I did miss having to put in some effort after a while. The Glyph of Mend Pet is amazing, but when I realised that it was so good that keeping pet food around had in fact become completely pointless, I was kind of disappointed. (I recently played with a lowbie hunter alt for a bit and it actually took me some time to get accustomed to having to feed my pet again... until I hit level fifteen, got the glyph and vendored all the food. Go figure.) In group PvE pets had become nearly indestructible as well, so you could just send them in and forget about them - what with the massive AoE damage reduction and all the "smart" raid heals flying around. (Gal'darah, Svala Sorrowgrave and Ick stand out as the few heroic bosses that I can remember off the top of my head that actually will kill your pet if you're not careful.) But if pets don't need training, feeding, healing or guidance anymore, what more are they than a passive extra damage ability?
The Survival single target damage rotation was actually reasonably interesting, but considering most of my time in five-mans was spent spamming Volley and nothing else, that didn't actually count for that much. And doing nothing but spam Volley the entire time? Bo-ring.
Do I even have to mention the utility? I still misdirected out of habit, but unless the tank was actually freshly dinged, threat was never an issue anyway and MD was in essence a wasted global cooldown (and a fair chunk of mana to be honest). And traps... who even knows how they work these days? I remember exactly one instance where I was asked to use my Freezing Arrow in WOTLK, namely the Pit of Saron run mentioned here. Conversely I've run into people that don't even know what "CC" stands for anymore. Sad times.
So, with all these factors taken into consideration, I played my hunter less and less (except to upgrade her helm occasionally). I kept her gear reasonably up-to-date just in case, and I did get to take her to ICC once or twice, but it wasn't particularly exciting.
Cue patch day. I logged onto my hunter before many of my other alts simply because I was curious about the focus change. After selecting a Survival spec once again I went to a target dummy, started attacking it, and was disappointed that I was out of focus after only two or three shots... for about three seconds, by which time I had realised that the resource was regenerating pretty fast anyway, especially with regular use of steady shot, and even the rotation didn't actually feel all that different. The basic rule of "use your specials when you can and use steady shot when there's nothing else to do" still applies.
More importantly though... Volley is gone! One of the guys in my guild was moaning about this very heavily, but I was actually really happy. As it turns out, Multi-Shot has been adjusted to serve as our "new" AoE since it hits an unlimited number of targets now, but it's not nearly as stupidly spammy as Volley, since you'll be out of focus after two or three uses. I went on a few heroic runs and my dps was about the same as before the patch too.
And then I followed a link from Rades to this post today, which contains this amazing flowchart illustrating the new buffs that different types of pet provide from now on. Now, I'm not sure whether hunters having all the buffs isn't a bit crazy, but - from a hunter's perspective... it's finally a reason to pay more attention to your pets again! After seeing this flowchart I immediately went out and tamed a raptor, a ravager and a wind serpent, which provide the only buffs that I was missing in my non-Beast Master stable, and then ran a couple of random heroics to start levelling them up. And as I was doing so I immediately started thinking about the group composition of each run, and which buff would be the most appropriate - finally something brainy to do again!
Now all I need is for Cataclysm instances to truly require crowd control again (the threat nerf in this patch already makes Misdirection useful again, even as - or maybe because - people continue to AoE everything), and my hunter will suddenly look like a very attractive and fun alt again.