I wasn't going to restart my WoW subscription, but I'm weak, so I got Cata for myself for Christmas...
On 80-85: Way too short, I felt - I did each new zone in one day each, dinging 85 early in the fourth zone. That's complete with loremaster achievment and end-of-questline achievments, though I skipped on stuff like the "bounce 20 times" thing in Hyjal.
On Worgen: I rolled a druid, have played her through all of Gilneas and she's waiting for me to pick her back up again in Darkshore. Fun zone, but only if you're a worgen - the whole place is *totally* empty if you're not. There aren't even any forsaken invaders to slaughter. :/ Also ditched my old, under-developed death knight (who got as far as outland and then I didn't feel like playing her anymore) in favor of a Worgen one. Sadly, you can't fight in human form at all, it would have been epic if you could just switch to worgen form for running. (Mostly I'd want this to keep the snooty brit voices of the Gilnean humans....)
On Goblins: Haven't tried that yet. I really should play some Horde characters too, but... see below.
On the new fluff: Anyone else feel like the Horde are growing noticeably more evil, especially the Forsaken? With Varian being all "death to the Horde", and Thrall being busy trying to keep Azeroth from falling apart physically, I can get Garrosh Hellscream being agressive. Haven't been back to Mulgore yet, so I'm not sure how Blaine stacks up to his father. But Sylvanas? Damn, I wanted to strangle the bitch after the Gilnean campaign.
On dungeon queues: OK, so I could kind of understand the 30 minute wait for each dungeon on Normal, seeing as everyone had probably moved on to the heroics by the time I bought the expansion. But getting to the Heroics and finding *double* the queue time? AAAARGH.
On the redone lowbie zones: I've played two characters through Elwynn and into Westfall so far (one of which was the DK, though - thought it might be a good idea to do some quests while I leveled my gathering skills...). Elwynn didn't have any major changes other than the new flight masters, but Westfall? The first blasted questgiver you encounter when you get there caused me to take a five minute break for gutbusting paroxysms of laughter, and Redridge is even better. After that, Duskwood was a bit of a disappointment, though, it hadn't changed a bit.
Darkshore promises to be an adventure, the whole place is pretty much impassable terrain now, and I was saddened to see some of the people you couldn't save during the first quest there.
On the new dungeons: Couldn't tell you, still waiting in the queue... Well, not really. I've managed Grim Batol and Halls of Origination, plus everything except the last boss in Lost City. HoO is hard, and since it's comparatively long it's really hard to get a group that'll do all of the four upper level bosses. (Seven bosses in a dungeon? Been a while since we had dungeons that long...)
SP