If I could uprate your comment to bright green, I would. This is a problem with player culture rather than the fault of designers in making healing difficult (given of course that they don't make it too ridiculously hard.)

I have played a holy priest since January 2007. In TBC I was in a high-end raiding guild and took every opportunity to heal, even when I didn't need the loot or the badges. Shattered Halls Heroic or Illidan, I was there. I loved the concept of people working as a group and using the utlilty their class has been granted to roll through difficult content. And I loved the fact that even with less offensive utility I could do so much to improve my survival and longevity; the cast-cancel rhythm of holy priest healing, downranking, chaining procs to regen ridiculous mana while still casting, taking breaks to let the five second rule do its job; basically everything Ghostcrawler says is 'boring' I loved because it felt like I was using the skills I was given in gimmicky ways rather than having a gimmick forced upon me by the designers, which is how mechanics like Serendipity feel to me right now and how I fear Chakra will feel in the expansion.

Unfortunately, In WotLK I haven't had a PC capable of handling 25 man raids and I've never been interested in 10-mans so I've been a casual player; this, to me, means gearing to what the limits of the dungeon finder will let me.

Well, I no longer do dungeons. This is because every single time I do queue, I without fail get a tank in ret spec with 15k health and green gear of the monkey or the whale, a rogue who spams 'gogogogog' (the last, superfluous G is the one that really gets to me), an AFK mage, and a hunter who decides he wants to tank. I get people insisting they go to the end boss because they're only there for their frost badges, people who drop the instant they don't get the loot they want, tanks who run into 5 packs of mobs and then bubble-hearth, DPS who stand in all of the fires of hell and nuke at random without paying attention to friendly banter like 'We should kill the Spellflinger first' or 'Could you interrupt the chain heal?' or 'Did you know you can tranq shot that shield on the Runecaster?' Essentially, people play like mindless drones intent on eking out the maximum DPS so that they can link meters after every trashpack, rather than actually playing their class for the utility it brings. And if they die, they spew bile at the healer or the tank, rather than looking closer to home.

Mostly I can keep this group of WotLK babies alive, but it stresses me out. I can feel myself getting tense, sitting in front of the laptop. In Cata, if they get it right, healing will be challenging and, I'm hoping, dungeons will recapture some of the same sense I had in TBC. But if I'm in the same position re: PC in Cataclysm and there's not a significant culture change, I'm going Shadow, because frankly my blood pressure can't take the rage that the average RDF player spews towards the healer when I can actually do something about it, never mind when I'm mana-starved enough that I can't.