VLC users that use firefox should have npapi-vlc automatically built with a firefox use flag or an nsplugin use flag. This feature is not implemented and it would greatly reduce users' frustrations. We would need to add a use flag to the ebuild as I could not find the nsplugin use flag for amd64.
well, no, npapi-vlc is a separate package for a good reason: with your proposal, changing nsplugin useflag would trigger a useless vlc rebuild and npapi-vlc should have the same keyword visibility as vlc