I really enjoy how Dragon Age 2 starts you out as an almost all-powerful version of your character then brings you back down to reality when you lose most of those cool abilities. It gives you a nice glance into the future as to how you can build your character. Varric is always witty and snarky at just the right times and the dialogue between the members of your party is a Dragon Age staple and brings a lot of character development to the table. The plot is fascinating and just when you think the game might almost be over, a new twist develops. The gameplay is pretty linear. Sure there are plenty of side quests to do (and they're actually worth doing) but don't expect too much wandering around.
Although the brunt of much controversy, I really liked the fact that there were homosexual romance choices. Yes, it dumbs down sexuality considering every single player is essentially bisexual, but at least it even has it as an option, which few other games do. (obviously Mass Effect comes to mind).
All in all, Dragon Age 2 is a great game which has replayability (I've already replayed it 3 times) and it is a fabulous prequel to Inquisition.