I think knyte's last suggestion of increasing the power of the APIs has the most potential.
I fully understand the logistics problems of having developers donate time.
Imagine an API that could, say once per turn be invoked to do things like:
* Change ownership and armies of any territory
* Apply diplomacy or income modifiers to players
* Publish a message in public chat (great for diplos, etc.)
* Send a private message to a player
* Award cards to players
* Eliminate a player or declare a winner
For obvious reason any such game would have to be a Practice game but it shouldn't take much imagination to think of some incredibly custom games and scenarios that would be possible.