I haven't yet downloaded your program, but it looks great. One question: does mp3Diags support ogg and more importantly FLAC files? Most of my collection is ripped into a lossless format (FLAC).
A lot of the functionality is MP3-specific. Supporting other formats is something that I don't do and don't plan on doing (but things might change in some undefined future.) For now I don't have the time to tackle such a task, nor any desire, since I usually can't tell the difference between a 256bps MP3 and a WAV, so I have little incentive to re-rip my CDs.
Anyway, since it's an open source project, others might step in to add FLAC or OGG modules (though I don't see it as very likely.)
MP3 Diags seems to be a great tag editor, but since at least 90% of my audio collection is in lossless audio formats (mostly Monkey's Audio, Flac and Wavpack), I find little usage for your nice tool.
I can see that MP3 Diags has been created basically for private purposes, but adding suppot for at least the most common audio formats like OGG, MPC, WMA, FLAC, APE, WV, would add more value to it and make it a complete tag editor.
At least for me the difference between a 320bps MP3 and a 900+bps FLAC is huge. So I would like to ask whether you have reconsidered implementing support for other audio formats. Of course I can imagine that this would be a mammoth task.
I see your point, but unfortunately support for other formats would take a significant effort and I simply don't have the time. The only thing I can do is provide assistance if somebody else volunteers to look into this and contribute code or take over the project.