Dragon Age 2 had its share of faults. The main ones that I can point out are: lack of environments and character development that was not good as in DA:O (imho). Both games had kinks with the endings, though I found Dragon Age 2 ending to be worse, because it hardly even matters which side you choose. In TW2, the political turmoil leaves everything uncertain, though some nations may come out on top and regain stability depending on your actions.
Most people who are hating on the combat in TW2 don't use Quen enough. Haha. At first I had problems with it, but after I started to use signs I got through fights without many problems. Played on Normal, so still felt the urge to say "F*ck yeah" every time I killed a rather large group of monsters.
Dragon Age 2 is a good game, although not very memorable (for me at least). I replayed DA:O 5 times, while for DA2, I simply reloaded the save to see the other ending (which as I pointed out earlier was almost the same. By the way, this is where I find TW2 (and TW1) to be superior. Actions have delayed consequences, which makes simply reloading and choosing something else impossible. TW1 seemed to have more of those though (or I am simply missing those "painting like" cutscenese).