Compilations at end?

[simoncn]

I don't see why it would be confusing for files with an ALBUMARTISTSORT tag to sort on that tag and for files without an ALBUMARTISTSORT tag to sort on the ALBUMARTIST value. It seems to me that the purpose of the ALBUMARTISTSORT tag is to provide a custom sort value in files where this is required by the user. Perhaps I have misunderstood your comment.

I agree with your comment about non-Latin languages. A Unicode character with a very large codepoint value could be used, perhaps this one: ?.

Edit: It looks like my attempt to paste codepoint U+2F9F4 didn't work.