An excellent RPG, only held back from greatness by the quality of its predecessor.
So for a sequel to follow one person's struggle from refugee to champion of one city outside of Ferelden... well that's not very epic now, is it? And that is the heart of the complaints about DA2 - very little can live up to its predecessor. But if you get past the fact that the plot of the sequel isn't as transparently epic as the original, you would realize that this is an amazing game.
The mechanics of this sequel are arguably simplified, but not for the worse. The classes, abilities, buffs, spells, potions, etc. are all here, but slightly simplified in a not unimproved way such that everything is clear and has its place. The skill tree and attribute upgrades are possibly the finest I have seen in an RPG in that you get all the information you need in making informed upgrade decisions. At no point did I ever feel this was a dumbed down game. The gameplay is excellent, though on normal difficulty it is fairly easy and does not require much in the form of tactics. If people weren't making such a big stink about it, I probably wouldn't have even noticed that the mechanics are slightly simpler than Origins.
The story in this game is subtle. For the first 15 hours or so, it feels nowhere near as epic as Origins. Later you see where Kirkwall is heading and you know that one of the major political clashes in Origins is about to come to a boiling point. By the time you finish the game, you'll realize how this ties in nicely with the lore of the Dragon Age world, and you get an idea how Dragon Age 3 will play out. Though that said, the ending is somewhat abrupt, and an obvious prelude to the next game in the series.
What makes this game shine are the companions. Sure, some of the companions in the original are memorable (I'm looking at you, Witch Of The Wilds), but in DA2, every companion is memorable, and significant. Each person has their own not-entirely-predictable personality, and for the most part they will surprise you with the emotional decisions they make. It might not feel like your choices have a significant effect on the world, but you certainly feel involved in your character's relationship with each companion. I would say this is the best Bioware has done to date on that matter (with the exception of Baldur's Gate where you might end up killing potential companions - which was pretty amazing).
If you were a fan of Origins, I implore you to give the sequel a shot, and ignore the criticism. Yes, it is not as epic as the original, but it is a compelling story and an amazing RPG that should not be missed. Do yourself a favor and play it immediately.