Long story short, one week into Cataclysm, and it is looking great.
For sure, some effort was put in areas where high level players don't really go, except
en passant. Such is the case of Darkshore and alike, which were heavily revamped due to the cataclysmic tsunami caused by Darkwing waking up. Flying in Azeroth is a long time wish, and specially Orgrimmar seems to have been 100% recreated, while Stormwind changed a bit in some areas, but essentially remained the same city.
What really looks great for me is Vash'jir. I did all the quests in this area with Netcownt and I'm now also doing them slowly with my other 6 chars (Mage, Rogue and Hunter are being left behind, the rest are trailing Netcownt, 4 of them dualboxing).
I still had no time to check up on the Goblin and Worgen starting areas, although in both cases, for me at least, a story link is missing that shows to level 80 players that killed Arthas, why are we going to interact more heavily with Goblins and Worgens now.
I'm now half way into Hyjal. The story background in Hyjal goes back to my beloved Warcraft adventures in the XXth century. Now it just develops a bit further.
Graphically, it couldnt be better. I'm still doing 50-60 fps, more detail, underwater movement, textures, etc, are stunning.
Questwise, it is also an improvement. We have much less optional quests, there is now a sense of duty, of chain questing that actually tries to achieve something. There are still those "kill 10 mobs", "grab 8 flowers", but there are also many quests where the player (this one is copied from LOTRO, by the way) impersonates the enemy (nagas), and some funny gnome adventures. Intermediate cinematics are also a good idea.
In terms of playability, I think it's too easy. Seeing hundreds of lvl 85 players after 1-2 days of the expansion being released is just ridiculous. I'm sure some of them farmed the same mobs over and over, and most quested without bothering to read one line, and are now gearing up in heroics. Ofc, each player is paying to play, and is free do to with his time whatever he pleases, and if he feels good by having 320+ gear level after 1 week of play, then be it.
Anyway, it is TOO easy. In LOTRO, in AION, in vanilla WoW, if you had more than one mobs on you, it was tough. If you had three, it was immensely challenging. In Cata, I go into Demo mode as a iLvl264 warlock and I can dispatch 5-8 mobs in 10-15 secs. I have more problems gathering them than killing them, although in some areas, respawn rates are so high you can simply stay on one spot for hours. It's probably that way that the first lvl 85 showed up, I'm sure.
I'm going slower, reading each quest, some times checking up on lore to see if it matches the RPG story outside of the computer game, and previous Warcraft games.
On Chromaggus, the PVP is..a nightmare. Alliance is outnumbered may be 5:1 or more, and horde are killing on sight with no remorse. Dualboxing plates should help, I thought, keeping them away. It doesn't. I cannot even get revenge, as when I try to, 5 of them fall on me in less than one breath. A nightmare indeed :) and it slows leveling a lot ! Oh well, it's fun too, yelling "filho da puta!" in my office :)