It’s a little embarrassing but we did get everyone to stop using the distutils features that don’t package very well in wheels; I guess it was easier for them than contributing to packaging; egg did a similar feat years before. So I think it is doable for better or for worse. A game developer will want to redistribute your library. They will submit a pull request “please include this bit of extra metadata”, and so it goes. The payoff would be better support for Python applications as opposed to using the Python interpreter as an application.
I think most of the extra metadata would be the responsibility of the application developer instead of the library developers. Imagine something like py2exe but during the entire development process instead of at the end. When you run your application, the subset of Python you’re not planning to depend upon would be hidden. Then you would be continuously ready to redistribute however much of Python when it is time to share the program.
The imagined tool would be optional, like virtualenv.
Since you might already get a subset of the standard library if you are using a Linux distribution, it could be surprisingly helpful to make it official.