Here are some suggestions based on my few days on GW. Feel free to sling dirt at me! ;-)
1. The front page search function is great, but the results are a bit hard to dig through. It would be nice if the results were neatly tabulated as Members, Groups, Comments, Forum Posts, Blog Posts, etc.
2. The entire site should be indexable by Google web crawlers. Not sure if this is currently happening. I realize the site has not been around long, so Google might not have fully indexed the site. A current search
of google looking only at genealogywise.com only seems to show groups and member pages being indexed. I think the more usable data will come from comments, forum posts and blog posts about particular surnames, areas, etc. i.e., Google should be driving users to GW when a surname is matched.
3. Don't show as many groups at the top of the main page. In fact, show the blog posts and forum posts at the top and reduce the size of the groups page. I don't think it's necessary to see that many groups on the front page. Perhaps have a group-only search box in that group box. I always find myself scrolling down to see the latest forum posts and blog posts.
Just my $0.02.