I find your dismissal odd. Respectfully I have to firmly disagree.
Correcting incorrectly tagged files can seem daunting, but if you take it in segments it will probably be less labor intensive than you fear.
I know how intensive it is. Also, if I were to have lost all my data on my computer and reloaded my files into Musicbee, wouldn't they would have to be edited all over again?
IMO Steven's limited time shouldn't be taken up programming workarounds for people's mistagged files, but I'm not the final arbiter of that, just a voice among many.
Hmm. So you think that the "Artist" tag of a music file should NOT include multiple artists, seperated by a character such as " ; "? A lot of people do this and in fact Steven's limited time was used to support this format for mulitple artists. So calling these files mistagged isn't really objective. On top of that, places such as Musicbrainz constantly have Artist tags with Artist splits like " ; " & " / " and countless other music players have the support for it.
There is an inconsistency within Musicbee. The library itself supports Multiple Artists (seperated with " ; ") but the last.fm plugin does not use this same support. That to me is a problem, and not simply a preference. Expecting everyone to manually go through every file and change the "Display Artist" is a workaround for a lack of consistency with the use of the tagging rule.
This change cannot be difficult to implement. I can think of two fixes:
1. Adjust Last.fm plugin. Just change the string taken as the Artist to be the text before the " ; ". This could be a custom setting (scope could be small or large), where users could choose the field used, to include all artists or just one, etc.
2. Musicbee Tags. Optional/Customisable rule for "Display Artist" which allows for it to only take the artist (text) before the " ; " in the <Artist> tag of the file.