An advanced feature would be to highlight how coupled and cohesive the code is of each project.
Figuring out how tightly or loosely coupled the code is and its cohesion factor. At times I completely refuse to use or contribute to a project if I find it very tightly coupled. But one may not realize this until its too late.
This would add a feature to Ohloh that no other site (that I know of) has and might reel in interested parties.
I know there are some metrics to measuring cohesion of code.