If only there was some graphical tool that allows the user to see conflicts, relax version dependencies, and of course rollback changes if things didn't work out.

Or an error message like:

    There's a version conflict. In order to resolve, try one of the following:

    pip relax-dep package1 >= 1.0
    pip relax-dep package2 >= 2.0
    pip remove package3

And then you would want to have

    pip undo

(Just brainstorming here.)