I haven’t seen any development addons for Domino Designer that could make it more social.
It would be great to have some integration that you easy could update what design elements or/and databases you are working with.
Also a easy way to update status in your projects.
I would be happy if you could have integration points in the designer that don’t require the use of creating a plugin.
Perhaps a side panel that can load an xpage and some scoped variables gives integration with the designer.
Java UI API support from XPages in the client wouldn’t be bad either.