Just Filler.
But what do you get in Dragon Age 2? You get Anders from awakening except he's not a funny mage with a dislike for the way things were run by the chantry. Now he's a hateful person with no personality other than "Chantry bad! Grrrrr!" Even so he was the only character that was interesting to me simply because he was possessed by the spirit of a friend you worked with in awakening, the expansion to the first game. Every other character is bland or cliche and not worth mentioning. Except Varric who is just comic relief.
The biggest problem with this game as far as I'm concerned is the story. The story for Origins is really great, almost all of your characters are very important to the story. But for this one your party members don't matter, except Anders as you will see in the end which will most likely make you hate him unless you're a little girl who loves gay relationships like everyone on deviantart. But what it boils down to is this has NOTHING to do with origins. It's essentially filler. The end of Origins left so many questions open, if you play the game right and do more than just look at the surface of the story. But all Dragon Age 2 boils down to is whether or not you prefer mages or templars.
In Origins, every part of the game allowed you to choose an outcome that would effect the game. Do you side with the prince of Orzammar even though he murdered his own brother and blamed it on his other brother? Or do you pick the noble who swore to the dying king the prince would not succeed him? These choices made you feel like you had a real impact on the game. In Dragon Age 2 at the end of the game you get the same ending no matter who you sided with templars or mages. Why bother even caring?
Possibly one of the biggest problems is the dialogue wheel. Some people love that the main character talks but the problem is it severely limits your dialogue. No matter what happens you get three choices that are clearly marked: A good guy comment, a joke, or a bad guy comment. Supper exciting. No need to try and put thought into what you're saying to influence a person.
You also can no longer customize your companions. You can't decide what kind of weapon they use, what kind of armor you want them to use, or anything other than what they give you. Origins let you customize everything but what default class they are. You can take Morrigan, a witch focused on attack spells and melting the flesh off you enemies, and make her learn healing magic so she can heal you as well as attack others. You could even make people blood mages or demonic soldiers. But in Dragon Age 2 everyone is stuck with heir preset skills. Sure you can choose what skills in their skill tree to use but there's no customization so it's basically just like leveling up in a game like final fantasy.
If you played origins and really enjoyed all the strategy and customization and having an impact on the story, you will likely be disappointed. But if you wanted an average rpg you'll like Dragon Age 2 just fine. Dragon Age 2 is a good game in it's own right, but as a sequel to Origins it's just flat out disappointing.