There has been a long running suggestion to split out the oauth provider and oauth consumer parts of the oauth plugin.
I started it today as a client needs some of this done.
The work is being done in a separate branch for now and will eventually go into a new repo.
I've released the oauth-provider gem which is the first very experimental version of it
If you need this functionality please help test it out.
I would like to do the following as well.
Only support Rails 3 and onwards and only support OAuth 2.
This doesn't change the oauth plugin itself but maintenance of Rails 2.x is a bit of a pain and slows development of this.
OAuth 1 support also should not be used for new projects IMHO. But I'm willing to keep it in if people really require it. Remember you can still use the regular oauth-plugin.
Other breaking features I'd like to add is simplify the code quite a bit and only store digests of tokens.