I don't like current --clear behavior, it's really useless because now venv just deletes everything from virtual environment.
You lose not only virtual env but files from your project also.
virtualenv cleans only <env>/Lib directory, that's much better.

I think venv --clear should cleanup everything which it creates (I mean bin/include/lib for Posix and Scripts/Include/Lib for Windows). Not sure about pyvenv.cfg