> > The idea would be to make this automatic in the byte-compiler, so the
> > packages don't need to worry about it.

Actually, now that I think about this,  wouldn't it make more sense to fix
this
on package.el instead of the bytecompiler?

Before upgrading a package, package.el could check if the package is already
loaded and then force-reload it after the installation. If there's a way of
knowing
the features provided by a package (look at filenames?) this would be
trivial.