Still waiting to get home from work, so here's my feedback
Zones and Quests
I overall liked the way the Zones were designed. Together with the Quest-Hubs you had a clear path throughout the zone. The thing I missed most at questing is an real EPIC Questline that forces you to quest all over the world for some higher purpose than just kill X of Y (i.e. Ony-Pre, Linken).
5-men content
I'm a little bit disappointed with 5-mens from their design because I never felt a real connection from the storyline to these dungeons. You basically went in, downed the 3-4 bosses got your loot and got out with some reputation. You didn't knew why they were evil or even who they were.
The second disappointment is the wing-type architecture of 5-mens. In Classic you had the Scarlet Monastery and LBRS/UBRS as wing dungeons. In BC all wings were for different levels nad had not that much in common, except some interior design. And Wrath is going the same way.
Raids
I really liked Karazhan from its flair, design and storyline. It was a really good starting instance and very well tuned. It also has optional bosses which make it very accessible for starters. As some other pointed out already, the step to Mag/Gruul and SSC/TK was a bit too steep. The same with the problem as a more casual guild which raid to make progress on and how to equip new players.
It was a good choice to change from 40-man to 25-man Raids, because you didn't need to number of people to get a raid started, so you didn't need to pull people with you just to have 40.
PvP
Not a huge fan of it as a Holy Priest, but i like having another way to get to your equipment and not to disturb PvE
Professions
Tailoring overpowered, changes made to Elixirs hurt alchemists like myself, but reduces raiding fees. Juwelcrafting is a must have for good equip. The rest is kinda OK.
Misc
I like the way Blizzard gave everyone more ways to acquire their equipment. You can do state-of-the-art Raid, you can do heroics for Badges and BGs/Arena. Some Professions offer good ways to good equipment, the only way i can think of, that is nor possible is questing.
Best/Worst
Best: Karazhan, Badges
Worst: Consolidation of unique class abilities like CC, Healing reduce from MS to Hunters, Rogues and Shamans for PvP. Please let the classes be unique in more than the color of their spells!