I agree, we should figure out what we can advise to users already affected by this, because this is not going to fix the userinstalled flags retroactively. So even if they update to latest libhif, dnf still might autoremove half of their system at any point in the future.

It appears this bug left a mess and no one is quite sure how to clean it up.  I ran dnf autoremove on two systems which both are running kde, and the list generated was different on both systems - even though
the packages on the list are installed on both systems.  

I've been blissfully ignorant of this, and got tripped up by installing and removing corebird of all things after I had the libhif fix applied.  So while that may be the solution going forward, it doesn't appear
to address the ticking timebomb.