So, these are my thoughts on Dragon Age 2:
To start with, the gameplay. I believe the gameplay in DA2 is a big step forward from DAO. In Origins, your characters felt so bloody clunky, they felt like tabletop miniatures being moved around, rather than seasoned warriors engaging vicious eldritch abominations in a fight to the death. It just irritated me to no end when my characters would shuffle around the enemy, or struggle to push past an ally that was in the way as they get into backstabbing range. In addition to that, the way the characters used their weapons felt clunky and uninspired. The dual wielding rogues felt no swifter than your greatsword wielding warrior. The way the warriors use their weapons is just so *meh*, there's no flare. The mages, however were OK, I suppose, nothing to write home about.
Compare DA2. No shuffling, no struggling to push past an ally as they get into position. When my characters fight, the feel like warriors, rather than tabletop miniatures shuffling around. Additionally, the way the characters use their weapons has improved. The dual wielding rogues feel swift and graceful. There's so much more flare in the warriors now, they leap when using mighty blow and the shield bash ability violates a few laws of aerodynamics when used. The mages also feel less squishy, especially when they engage their foes in close combat (that's not to say they aren't squishy, they are, very much so).
The leveling system in DA2 is also improved. Your abilities aren't tied to your stats, so you don't have to wait until you meet the prerequisite stat mark, which took a long time in Origins due to how few stat points were given when leveling up. Skills trees are no longer linear, so you don't have to waste skill points buying useless abilities. Additionally, I must say the Reaver specialisation has been greatly improved. I've always loved the idea behind the Reaver, but due to the way it was implemented in Origins, I just didn't use it. Now that it has been improved, this is no longer the case. No longer is Blood Frenzy a sustained ability, rather it's a passive ability. Devour targets a single enemy, rather than affecting corpses only. The other specialisations aren't anything to write home about (though I am rather saddened that they got rid of the Arcane Warrior specialisation).
Now, I must say that the decision to give Hawke a name and a voice was the right choice. The Warden in Origins felt like a big mass of inconsequential nothingness, he never reacted to anything, EVER (aside from the death of Ser Jory and killing the Archdemon). He ended up feeling like a McGuffin, or a Chekhov's gun, a plot device rather than a character.
Hawke, on the other hand, feels like a character. He reacts to things, he cocks an eyebrow when something puzzles him, he facepalms when something stupid happens and his voice reflects the mood he's in. All of this comes together and makes Hawke feel like a proper character. This, however, has the added result of narrowing down your conversation options to about three. I don't mind it however, I would much rather have limited choice and a proper character as my player character than unlimited choice and a plot device as my player character. I should probably point out that my opinion stems from the fact that I don't like "blank slate" characters.
As for the voice actors chosen for Hawke, I must say, Jo Wyatt, the voice of, Lady Hawke has the better voice actor, her husky voice is heaven to the ears...
*ahem*
Additionally, Jo Wyatt, can emote better then Male Hawke's Nicholas Boulton. An example would be where Hawke's mother goes missing, Lady Hawke genuinely sounded utterly terrified, whereas Male Hawke, not so much. However, that's not to say Nicholas Boulton is a bad VA, he's a brilliant VA, it's just Jo Wyatt is better. However, I must say, the way Nick Boulton channels Brian Blessed during battle makes the fights so much more enjoyable "FOLLOW MY LEAD!", "NEED MANA!".
As for the supporting characters, they're all great in their own special way. It would take too long for me to describe them all. However, one thing ticks me off greatly.
Anders.
In Awakenings he was this snarky, womanising, laid back sort of fellow, a real great guy. Come DA2 he's this whiny, pathetic, little... thing, I half expect him to bring out the Linkin Park any moment. I absolutely hate the change Anders went through. Though I have to admit, all my hate stems from the impotent nerd rage that arose when the writers took Anders in a direction that I didn't like, and I have to (grudgingly) admit there's a strong justification storywise.
I found the storyline very refreshing, it was no longer about a hero saving the world but rather about some guy and the stuff he gets caught up in. It's a more personalised. Some people say the storyline is too segmented, I believe it adds to the story. A real life doesn't have an overarching theme, or a main conflict, or a main villain. A real life is a series of random events that have no relation to one another.
To be honest, I personally think DA2 is better than Origins, it improves everything Origins had, and adds a little more to the mix.