It's been revealed that Dragon Age 2 will have a campaign that's shorter than Dragon Age: Origins. However, it will still be longer than Mass Effect 2's.
The news comes from the game's executive producer, Mike Laidlaw, who said "I'd say it's a bit longer than Mass Effect but shorter than Origins. The game will take longer with side quests. At the same time, you can get through the story quite a bit faster because so much content is off to the side."
Essentially, this means that players who don't want to do all of the extra stuff won't be punished with expanded gameplay, but there's still plenty of lore for those who want to be fully embraced in the title.
Source: PlayStation Universe