It is meant as a joke -- but also planning to fix these issues ... apparently this was the right place to bring it to find all the situations where it doesn't work correctly :)
Rather than rotating through the entire BMP, I would suggest instead using Unicode's localized collations, and just rotating every character that's part of a fully-orderable "alphabet" set through that set according to those orders. (This means, for example, rotating Japanese hiragana, but not kanji.)
