I understand why PC gamers would be worried of course. If it's not the same DAO they know and love, why call it DA2 right? Well, the way I see it, BioWare gave me my money's worth with the original, so I'd wager they would only improve on what they had before, even if some of the new and exciting additions they add, may mean the loss of previous features. It's all about weighting in on the changes, to see if they are worth it. Now, I agree with have seen next to nothing about the game, so it's more understandable that people will be worried. I probably sound bitter with my responses, but that's just because the more time I spend on the internet, the more I notice how pointlessly bitchy some people are about these things.
Now, I will say I will be just as furious as the next guy, if these "changes" dumb the game down in any way, or make it more "streamlined" in a cheap way. Those types of changes are rarely good. But for now, I see no reason to think that's the direction BioWare is going for.