There's actually a fair bit to like about Dragon Age 2 but compare it to Origins and Bioware's other RPGs and it falls short.
The combat is basically the same as Origins but faster and nicer to watch. I really liked the backstory and lore. The choices you make aren't all black and white and there are some good characters woven into the fantasy. The art and music deserve a mention as well. The main flaws ate that the game feels rushed and unambitious. Levels are recycled so you can end up fighting through the same cave or sewer four or five times.
The story makes it feel like a spin off rather than a sequel to a fantasy epic like Origins. It's a bit aimless, takes twists that don't make a lot of sense and the ending just sets up the next sequel. Importing saves and making choices never made a lot of difference which was a real shame. It's not a bad game, just don't go into it expecting a lot.