Feeling like an old LP, repeating always the same whining. This is another old request from me: please do make the Branching panel really important, do not restrict it to a size of 800x600 and do show all branching sources, also those originating from advanced actions.
So with my work flow where advanced actions are almost always present in files, I often have unlinked slides. But it is due to the fact that branching is caused by advanced actions. The idea for the Unlinked slides panel was to detect 'orphaned' slides, that would never be visited. That is not totally the case however. If you have only linear projects you'll never have unlinked slides, if you are doing complex branching, conditional branching, this can be the case however.