I know, I've seen it before. It's very limited though.

I think that the ID3 tag support should be provided by a separate module.

My thoughts exactly, though I was thinking of MP3::Info. The idea is to have an --mp3 switch require the module at runtime, then have code that provides the information from the ID3 tag in variables like $ARTIST etc. Afterwards they're checked for changes just like $_ is. Assuming you have names like 02 Falling.mp3 you could then do something like

rename --mp3 '$_="\L\u$ARTIST/\u$ALBUM\E/$_"; $TRACK=0+((/^(\d+)/)[0])
+' -z *
[download]

and have it end up in Spicelab/A_day_on_our_planet/02_Falling.mp3 with its ID3 tracknumber set properly.

Adding similar mechanism for EXIF data would be simple (and a good idea too - I didn't think of EXIF, thanks!).