The game is pretty different to other MMOs (and it is a MMO this time, rather than a CORPG).
I think a lot of the negative feedback you're likely to hear will hinge around people who wanted something different. The game is simply very different to GW1. Is it going to be everyone's cup of tea? Definitely not. But thus far, it seems a polished, lovingly crafted game to me. You can tell the design team poured their heart and soul in to it.
The graphical style is beautiful and unique. It's cartooney, but in a mature way. I actually prefer this kind of style, purely because ultra-realistic graphics age very quickly. More stylized graphical presentation tends to last longer without looking like crap.
I found the responsiveness of the game to be crisp: push the button, ability goes off quick-sharp. That counts for a lot.
Some of the classes have a very unique feel to them, although I haven't really got very high with anything yet. The Mesmer in particular has a very different playstyle, something I haven't really seen in a MMO before (and I've played a fair few). Engineer is fun, but at low levels feels like a WoW hunter without a pet (I don't have any turrets on mine yet). Guardian seems very interesting indeed, although I didn't play with it enough yet to get a good feel for it.
The sound/music is excellent, although the in-game default settings aren't balanced very well. The spoken lines were often drowned out by soaring music in combat events, so I rectified that by simply turning the music slider down a good whack. I like to hear character speech over everything else that is going on, but YMMV.
The personal stories seem like an interesting addition. On the one hand, they're a lot more linear than those found in SWTOR; you can't choose dialogue options and the scene plays out without any input from you. On the other, they're a composite story made up from various choices made at the start of the game. Your character won't necessarily have the same personal story as another member of your class (unlike SWTOR, in which character shares the class story, just not their dialogue choices). I found the Charr backgrounds particularly interesting; my Charr Guardian story really does feel different to my human engineer. The backgrounds do a good job of capturing the feel and flavour of each race. Choosing things like patron deity or faction only serve to add flavour.
Some notable items are missing: no system to open a trade window with other players (ugh!), no ability to switch instances if you end up separated from a friend you want to play with (annoying, but can be worked around by logging out/in most of the time), and as near as I can tell, no ability to adjust mouse sensitivity. This isn't the finished product though, so perhaps they're just not in yet.
My wife is also playing, and this is the first MMO ever that she has jumped into and liked from the very start. She grew to like some others (e.g. WoW), but it took a while for her to get into them. GW2 is the first MMO I've known her to be excited to play prior to its release.
Just some early thoughts, YMMV.