Haven't finished the game yet. You have to think of DA2 (not DAO2, btw) as a completely different game from the first one. By now you know, the main character is different, the companions are different, there's the ME dialogue wheel, etc.
If you just take it as a new game, a spin off, but not a sequel, of Dragon Age Origins, you'll be just fine. I like it, but I don't "love" it. Some will "love" it and think it's the greatest ever. Because it copies ME games, it is not as "original" as it might have been. It took the Dragon Age name and the ME mechanics to make this game. It took some characters from DAO - so far, I've met Flemeth (you see her in the demo, too), Bodahn Feddic and Sandal. There's Cullen the Templar. There's the duelist, Isabella, who is a companion in this game (who stole her body from Miranda of ME2). The Qunari now have horns.
The journal works very well. (I like journals that just give what quests are open(Rumors, Main, Companions, Secondary, and Side). There's a mini-map in the upper right corner of the screen, as well as a regular map. Both are clear and easy to see. Inventory works well, though you can't change the armor or robes of companions -- it upgrades itself -- but you can change their weapons and jewelry (amulets, rings, belts).
Yes, the combat is much faster and flashier, and some people are extremely impressed. It IS impressive but...it isn't the end all and be all, for me.
One thing, after playing now for a day and a half (I had two days in a row off from work for a change) is that -- yes, I am comparing DAO and DA2 now, hahaha! -- the companions of DA2 are not nearly as fun and compelling as DAO. The DAO companions were just really memorable, and the DA2 companions are, well, plain vanilla. I think the writers tried, but the dialogue between DA2 companions were flat.
So, as it turns out the DAO camp dialogues were more revealing and the banter and bickering while traveling much sharper (and funnier).
Also, most of the story I've played so far, takes place in the city of Kirkwall, with a few side trips in the country outside the city. I don't know about other players, but it "feels" a bit claustrophobic.
Haven't read many reviews, just one, and it was a glowing 94 (out of 100). Can't say I can get all that excited after playing it for a while. I found that what I have played so far is almost getting monotonous, just one quest after another, of just "helping" people who can't seem to take care of their own problems. After a while, you start not to care. (Of course, the whole idea is to earn enough money to finance a Deep Roads expedition which, for some reason not yet obvious, is part of the main quest.)
It could be my imagination but it seems there's not as much loot, and there's loot that's called "junk". Dragonling eyes, torn trousers, frayed rope, empty stained bottles, flawed gems -- that you think, in the beginning, might be spell or potion components. But they aren't.
But so far, DA2 has been enjoyable, the trainer worked with no problems. I won't give it a "grade" yet since I haven't finished the game, just that IMHO it isn't a 94 (so far).