As for building a "better robot" I would suggest you read this:
http://people.clarkson.edu/~jcarroll...R.20091204.pdf
(If you have already seen it, that's great) It breaks down the process of building a robot and the importance of not over-complicating a robot beyond your team's capabilities.
Boltman's post is super important along with many of the other posts, I'll try to post more later, but it looks like you have a great start with the suggestions so far.
Good luck!