Let me state it from the beginning: I liked DA:O much more. Now, something more specific, bad things first:
- fighiting: it's really fast (too much at times, at least visually: animations are really too fast, they seem to be flashing at times), but almost each fight as been made "artificially long": you start fighting 8 enemies, but when you are almost done with them some more jump in from unspecified hideouts (why wait for your companions to be dead, anyway?); some are really "ridiculously" long: how come there are many groups of 15+ bandits going out at night? why don't they conquer the city? they sure have the numbers!
It gets somewhat boring (at least, you expect more enemies to come out every now and then during a single fight), and many "ordinary fights" get too long to end.
I almost felt like they intentionally made fights longer to compensate for the shortness of the main storyline.
- visual look: many things have been completely changed. The darkspawn (!!!) for instance, now are really less horrible and "monsterlike"; the elves vary in appearance: some are almost manga-like, some look a lot like the aliens in the Avatar movie (only with human colours and proportions), and some look decently "elvish", but still far from the beauty and grace of the elves you can admire in DA:O (very human-like).
- exploration and areas: you have mainly three setting (with short exceptions): city at day, same city at night, nearby mountain wilderness. This thing is bad enough as it is, you really feel like "caged" and the setting gets boring at times (forget about varied settings from forests to big cities, from arid mountainside small town to a village on snowy peaks, and so on, as in DA:O). But the thing that almost outraged me is the map recycling. There are something like 3-4 maps for all the caves or hideouts or underground complexes you go in, they are just oriented in different ways, and some areas may not be accessible. BUT that's not all: they didn't even bother to "mask" this recycling of maps, since you always see the full "standard" map of the area (including the parts you can't access to), and the unaccessible parts are made so by abandoned carts, or worse, stone doors! Yes, you see the doorway, but a wall of stone in it. I mean, this could have been acceptable10 years ago, but now it isn't, especially in a "high ranked" game like this. Bioware guys, I really love your games (starting from your old-times classics), but you can't make slips like these.
Furthermore, in some part of the games you find yourself forced to explore from scratch the same area you explored before (years in game-time). Boring.
- story: it's nothing exceptional, it has its bright moments, but it didn't "catch me" like the one in DA:O, it feels much less "epic" and you feel a lot less like the "main character" of it. There are a lot of side-storylines (some more interesting than the main storyline), but I had again the feeling that they where put there just to "compensate" for the "not so good" main storyline
- game lenght and story: it's less than half as long as DA:O, but by the final part you are almost "waiting" for it to end (at least, it was so for me), as the game feels like "dragging itself forward" at times.
Now, the good stuff.
- as I said, the storyline(s) has its bright moments
- the dialogue system is now styled after the one in Mass Effect, which I like a lot, I find it very clear and functional (although misleading in rare circumstances)
- the narrative structure is very interesting, expecially at the beginning
- most of the companions are really interesting
- the ripercussions of your choices are often "concrete" and have effects on more than just "companion X approves"