So far I've been talking about redesigns and templates and main page revamps. But there's still a vitally important factor to consider: the look of the wiki.
I think the colors are fine, but it's possible we may need a new wordmark. More pressing is the background. I played with it a while back, choosing fern pictures. Eventually I settled on a plain old green background. Although it's fine for now, I just don't think it cuts it. It should be customized in some way, perhaps with various dinosaurs and fossils.