Last night I specifically queued for Wailing Caverns and Shadowfang Keep, to make sure that I'd get a chance to run them before they fell out of my level range. I feel like I have to throttle my gameplay very carefully right now to not miss out on content I want to do, which is really rather bizarre.
Wailing Caverns was a bit of a disappointment because it didn't appear to have changed at all. Now, WC is one of the old instances that I'm slightly less familiar with, so I can't completely exclude the possibility that they removed a side passage or two, but it looked exactly the same to me. The changes that the developers were talking about at Blizzcon, where they mentioned making the instance less confusing and putting all the bosses into separate rooms definitely haven't been made. I can only guess that they ran out of time before the Shattering and that this is something that they'll patch in later - or at least I hope they do, because otherwise WC is going to feel horribly outdated compared to other instances.
The only positive change that I noticed, other than the quest givers sitting inside the instance now, was that the Disciple of Naralex actually runs once you start the escort event now - instead of walking at a snail's pace, as quest NPCs that claim to be in a hurry are so often wont to do. Thanks for that.
Still, for what it's worth I enjoyed that run, because I had a group that was both nice and competent. The trip to Shadowfang Keep that followed afterwards was exactly the opposite.
SFK itself has been changed drastically, just like the Deadmines, but I couldn't really warm to those changes yet. In the Deadmines, even before I had played through Westfall to learn about the story behind it, it was at least somewhat apparent that we were breaking up a rather shifty operation in those caverns. I mean, mining monkeys? That can't be legal.
SFK on the other hand just confused the hell out of me. Gone are Arugal and his werewolves, and instead there are... evil Forsaken? The quest giver at the entrance greeted me like an old friend and went on about avenging some insult against Sylvanas, but I had no clue what the hell he was talking about. The fact that three of the bosses looked like they were identical triplets or something didn't help either.
This basically strikes me as story gone wrong: instead of the background enhancing your experience by giving you additional motivation to clear out the evil guys' hideout, the story is your only motivation to take action... otherwise it's just random. I mean, this stuff was clearly designed to be a sort of follow-up to whatever happens in Silverpine - about which I've only heard good things - but without that background it's just weird. I guess I'll have to roll an undead hunter soon and maybe I'll change my mind once I understand what it's all about.
Like in the Deadmines, the new bosses are considerably more complex than what you'd usually meet in this level range, and pretty much all of them have some kind of big flashy move that you're supposed to avoid. Oh, and the first boss seems to have no other purpose than to scare the crap out of your healer. You're dead! No, you're not! You're dead! No, you're not! Arrrgh.
Most of my unhappiness with my SFK pug came from the fact that my entire party absolutely loved standing in the bad stuff, even though several of them wore heirlooms and really should have known better. I didn't have the mana to save them all the time and there were multiple deaths. On the last boss we even wiped twice, though our warlock managed to finish him off on our second attempt as the last man standing.
The tank also aggravated me because he kept pulling whole rooms at once, which led to loads of unnecessary damage on him as people were killing things off one by one, so I was constantly oom and left with no time to regain mana as he kept charging off into yet more mobs over and over. This sealed my decision to not queue as a healer anymore until I can get dual spec at thirty. At least then I won't have to constantly feel guilty and question the validity of my off-spec healing whenever someone dies to playing stupidly; I'll know that it's their fault.