Hey, I'm Matt Lee, founder of GNU social.
You're right, there's little imagination going on there. It looks a lot like Facebook.
Right now, there are over 500 million users of Facebook, and approximately 250 thousand users of GNU social or a service based on GNU social and StatusNet code. Convincing those users to move to decentralized social networking, whether its with GNU social, Appleseed, Diaspora, etc is going to be a tough job no matter what, and we should do everything we can to make that easy for people.
One of the biggest problems with Facebook is that its ever changing UI causes people to leak their private information all over the place. I intend for that to not be the case with GNU social, but as we support themes out of the box, I do expect there will be some inconsistency.
Finally, we have a design contest right now -- http://twitter.com/timberners_lee/status/19860898949 -- for new themes and styles for GNU social. If you have some radical ideas, please share them with us and help us making decentralized social networking better for everyone.