Hello @weex and thank you for your interest. Right now the development of diaspora* is pretty slow so I don’t think a plugin system, which looks like a big task, is going to be added soon. However, in the next major release, diaspora* will provide an API, which is very useful for developers if they want to build some kind of simpler interface.
The only last blocker for that next release is to provide a UI to the migration feature, so if you want to help on that topic, you’re welcome!