What do the short-comings of players have to do with MP3tag?
If you want to append a string or field to the contents of another field, see the FAQs:
If you really add the artist to the TITLE field, then consider to use a different separator between the 2 bits of data like the underscore - this would make it easier to separate the data later on, when you switch to players that can deal with compilations and you want to get clean fields back. The hyphen is also frequently part of the title so it may lead to unwanted results.
You could also see if setting the field COMPILATION to 1 helps your players to identify compilations.