> I think this is a good idea, but I think that implementing 
> extensions and new modules is relatively easy (in most cases)
> but deciding on the best interfaces is not.

Deciding on interfaces is probably the most important (and difficult)
problem in library design. Finding suitable (=intuitive) names for
functions alone can be a difficult task.

No sensible contributor would check in changes that effect the interface
without discussing this with other developers/contributors before. So if
there is a good means of communication (e.g. a specialized mailing list)
and if people adhere to strict rules concerning check-in, I am quite
convinced that this would work well.

Regards,
Markus Mottl

-- 
Markus Mottl, mottl@miss.wu-wien.ac.at, http://miss.wu-wien.ac.at/~mottl