I think we would still need a configuration option that does not involve Java. Other than that, I don't really see too many issues. As far as names, it could possibly default to the name of the plugin jar or something else and first one wins, second one fails. We could also namespace, kind of how you see with eclipse. Honestly though, nothing sounds much better than a simple config file with the jar, same name or whatever, that has the plugin name or url. Probably that's the default minimal setup - even if you can delete that file and run with some default names or whatever for plugins that don't require any config.
I think the path is obviously right - you see it used plenty elsewhere, and it resonates with me. But I think Hoss is right in that the common case will still need configuration. I don't see how the two points argue with each other though.
We will need to be able to configure with a user friendly format - most plugins will have that - if not just to show the user what can be configured. There is no reason we have to require it though. Some plugin might simply be there to insert some custom code on startup.