You know, the more I play it, the more it grows on me too. Despite all the flaws I listed, it still shows pretty amazing potential. The characters are slightly better than Origins, but what sets them apart is the banter; companions form relationships between themselves, and Hawke even sometimes comments on it based on the dominant personality you assigned him/her. I really like seeing Varric take every companion (especially Merill) under his wing and using his vast network of contact to help them, or watching Isabela (the game's worst character if you ask me) and Aveline (best character) bicker in a way that makes Alistair vs Morrigan seem tame. Seriously, the party banter in DA2 is pure gold.
Also, it's funny, but the two parts showcased in the demo are probably the game's two worst part (especially the godawful prologue). Several (not that many, however) quests actually have several possible endings, and I really dig the fact that companions sometimes help you resolve situations (Varric can bluff like the best of them, Fenris can use his knowledge of the Qunari to make them more comfortable towards you, mages can help when demons are in the picture, ect.). Also, I just finished a long, rewarding and very open-ended quest that was made available because of an action I made during the first act. They said actions would have more consequences and they do actually deliver. I mean, there's already a pretty nasty consequence to a choice you make at the end of Act 1.
And I cannot express how flexible and just better the skill trees are this time around. My carefully built sword and board warrior is capable of using talent synergies to inflict massive punishment, it's so much more rewarding than Origins's linear 2handers = damage shield = tank system. Specializations are also much better, they actually have unique playstyles and powerful abilities, while in Origins the Arcane Warrior was the only good one (read, it was blatantly overpowered).