1. For starters (besides other internal stuff), we were the guys who needed Shibboleth support. You might recall there were a few pull requests from a colleague of mine regarding that :)

2. No, we had to tweak the source, so I don't think the packages were useful.

3. Static pages, hooks and merge approvals would be right at the top of my list. Audits would be nice to have, but we figured out how to do that on our own.

Also, issue handling needs some improvement. We just couldn't map our Trac workflow to it - but that's a fairly longer story, and it would probably be the same if we used GitHub.