One of the hard limits that people have identified in Team Foundation Server is one on the number of Team Projects that can be created. This is really a fundamental architectural issue which I hope that Microsoft addresses in a future release. If I was looking at this challenge I would be wondering how I could remove this limitation whilst still adding great new functionality.
An idea that I had was around providing some of categorisation facility so that rather than the project list containing a complete list of projects, it just gave you a search form. I could see this kind of facility becoming a valuable asset within a development organisation because the categorisation (like everything in Team Foundation Server) could be made extensible.
I can imagine a time when your corporate TFS installation has something akin to a software map – ala SourceForge and Trove.