Eurogamer still haven't reviewed the WoD expansion for some bizarre reason but it has made one of their games of the year, so I'll direct you to the excellent write-up by Oli Welsh there -
http://www.eurogamer.net/articles/2014- ... of-draenorMe and the chaps have been back into the game since the expansion launched on November 13th so we've had over six weeks at it now, which I think is time enough to form a decent opinion about the game in its current state. (It should be noted here that we started playing in Burning Crusade so whilst we technically missed vanilla the original vanilla zones were still untouched in Burning Crusade so in that regard we've pretty much been there since the start.)
To avoid going TL:DR I'd say that WoW has never been better than it is now in WoD, it's like the atrocity of the pandas never happened and the game is right back to its fire and brimstone roots, in fact, it's arguably as good as the Lich King expansion, and that's saying something.
The Draenor zones are great fun to quest through, I levelled one of my characters from 90 to 100 exclusively through questing so I saw every new zone to completion, to the extent that I finished off the final zone despite having dinged 100 with loads of quest chains left to complete, because I wanted to see how it all panned out.
The dungeons are pitched somewhere between Cata and LK difficulty I'd say, normal modes can be pretty challenging, heroics can be brutal, and challenge modes demand a very together group (you can't really get golds with randoms, it needs a good guild or friend group). Looking For Raid remains a bit of a clusterfuck IMO, you just have to look at it as a loot machine, normal raids however offer a solid and substantial challenge.
Professions have been massively overhauled in conjunction with the new garrisons. Every character gets their own Level 1 garrison at the end of the opening quest chain at Level 90, and as you level up to 100 you can upgrade the garrison to Level 2 and then 3, and within the garrison you can create a number of buildings of your choice to assist with professions, gear, or just stuff for fun like the Goblin Workshop which produces a new invention every day to have a play about with. You also get your own mine and herb garden which has basically rendered the gathering professions dead in the water and destroyed the gold farmers.
TBH the garrison is pretty much a whole game within a game so I'll not bang on about it too much here, sufficed to say there's a whole section dedicated to it at Icy Veins. One of the results however is that you can 'do' all the professions to an extent without actually being trained in the profession, so for example if you make an Alchemy Lab in your garrison you can issue work orders for potions and flasks even if you don't have the Alchemy profession.
(The long and short of it is that garrisons allow near total self-sufficiency for just about everything, albeit with time-gating, so if you're not one for getting involved with the economy of the game and the auction house, you don't have to. But those things are still there for folks who like them.)
For someone who doesn't like MMOs I can't see the new expansion converting anyone to the cause, at its heart it's still an MMO with MMO mechanics, but for folks who do like the genre but have fallen out with WoW and/or other MMOs over the years, I'd say that WoW in its current iteration is as good as it's ever been.
We've got a fairly fluid group of six/seven people but we always manage to get together a five-man group for Saturday nights and we're putting ourselves up against the heroic and challenge mode dungeons with gear that's 'just good enough' to really push ourselves, and thoroughly enjoying it. Besides that we're doing regular tourist runs through old raid content for achievements, mounts, transmog gear and stuff like that.
I was so disappointed with the pandas that I wasn't keen on returning for WoD but was eventually talked into it, so I agreed to give it a go but with the disclaimer that if it didn't really impress me, I was going to be straight back out again. Now six weeks into the expansion I very much suspect I'll be fully subbed up for its entire duration and keen to see next one too.
As a final note the game has put on over three million subscribers since the expansion launched, to take it back over ten million again for the first time in a long time.