Maybe it's just because I write for a living, or maybe it's because I spend 99% of my free time examining these sorts of things, but I really, really liked DA:O's characters better. They were so much more developed, fleshed out, and believable. Alistair was hilarious, especially when paired with Morrigan. Morrigan herself was distant, cold, but had a side to her that was neither. She was complicated and real. Leliana was her own shade of interesting; bubbly on the surface, but with quite the interesting past, her own set of motivations relating to both you and her religion. Oghren, Shale, Sten, Zevran, Wynne... They all had their own wants, needs, pasts and futures. They were believable, and over the course of, what, a year? you got to know them in and out, as friends and battle buddies.
Move to Dragon Age 2, and you have a cast of characters that are horrible stereotypes and mashed up character attributes tossed together in a salad bowl, mixed up, then pasted together with duct-tape and elmer's glue. There were two characters out of the entire group that I thought were well developed, thought out, and realistic; Aveline and Varric. Aveline followed the path of an excellent character. Again, she was well thought out, her emotions were believable, her motivations made sense, and she felt real. Varric was similar. The rest of them... it was like watching a low-budget anime. You've got the shy one with a secret in Merrill, the androgynous dude with a bad past in Fenris, the outgoing big-boobed chick in Isabella, the foreign guy with Sebastian, the gay guy with Anders, and in my only playthrough the sister with what could be a brother complex. So original!
The worst part about DA2 is that you have seven years to get to know these people, who they are, what they want, etc. But by the end of it you know very little more about them than you did at the beginning. And they don't seem to give a damn what you say or do to them. I had sex with both Isabella and Merrill throughout my playthrough. You know what they said about it? Not a thing. Isabella kept saying "don't hurt Merrill, she's so sweet" while I dragged her to my bed and did the deed, and Merrill continued telling me "Isabella's like a sister!" while we snuggled in bed together. Seriously? I fucked your would-be sister, and am now sleeping with you, and you don't even care. Awesome, that made things feel really believable. I felt like I was reading a fanfiction.