See this ticket for details behind the deprecation and subsequent removal of the feature. Setuptools 3.0 raises an ImportError installing cffi.
I can put together a pull request.
I started work on a pull request in jaraco/cffi, but it sounds like Alex has beat me to it, so I won't be making the pull request.
Sorry for the fuss. Setuptools has plans to improve the experience in the future.
I've pulled setuptools 3.x from PyPI and backed out the bootstrap script (back to 2.2). I plan to restore the Feature feature until it can be more effectively deprecated.