> Unloading a <pkg>-autoload.el should be a fairly unusual occurrence,

> so most users should be unaffected.

True, but you're introducing a fragile code path that is only called

rarely and under possibly surprising circumstances. I'm imagining

things like an unexpected package left in the old package-user-dir

causing an oblique side effect through its autoloads that weren't

unloaded quite right -- not fun to debug at all, especially since

package.el will insist that the troublesome package isn't installed!

It seems like we should avoid fragility, even if said fragility

probably(TM) won't affect most users.