In despair over adequate tag handling I just gave up, years ago. Different players sometimes screw with id3 tags, (e.g. re-tag things like track, year, genre, etc) or use id3 in ogg, or worse. What's more, field lengths can be an issue, as can field counts, etc.. I tried folder hierarchies, too, but gave up on that: tagging is really necessary for cross referencing purposes. My current solution, which is highly sub optimal, is just to dump all files into one big directory (4,567 and counting) with elaborate names, then symlink to multiple hierarchies.
It's some work maintain, but so long as music players don't insist on automatically moving files everything functions. Everything is easily findable by simple file name search in the big directory, or by drilling down the hierarchies.
It would be nice if it were easier, and if more meta data were supported than I can cram in to the file name, but nothing else I've tried approaches this for usability. I wish I had better news.