> Gemini is designed to be difficult to extend without breaking backwards compatibility, and almost all proposals for expansion on the mailing list are ultimately shot down.

This could lead to some interesting adaptations. I'm thinking like the way usenet, news-groups were adapted to store and transmit binary files in the form of NZB's. So while the underlying protocol remains pure and simplistic (relatively), the overlays and adaptations build upon it may bring unweildly levels of complexity. Not inherently good or bad, but interesting to think about.