There would be absolutely no difficulty writing synched V1 and V2 tags (or just V1 tags, or just V2 tags, or removing existing V1 tags and outputting files with only V2 tags, or removing existing V2 tags and outputting files with only V1 tags, etc...) using the ID3 library. It would also be possible to merge the information from the player database with any tags that might already exist in the files (ie: change title/artist/etc, but preserve all other frames of a V2 tag, such as "encoded by", "comment", "encoder settings", etc.).

Which of these abilities will make it into JEmplode, I'm not sure, but I'd be very surprised if none of them did...