Unlike the -e solution, it wouldn't make the command significantly more verbose than the default option.

You could also print a list of commands for the specific options (or allow for index based selection) in cases where there were collisions.

kew dir <album name> (sometimes it's necessary to specify it's a directory you want)

kew song <song> (or a song)

kew list <playlist> (or a playlist)

The directory can be an artist or an album, so there's still ambiguity there. But kew cannot differentiate between the two. It matches against files or against directories.