I think XML is overused and is a big pain for a lot of things it's commonly used for (like config files!). However, I do think mixed case and CSV were both good advances and generally a win over those old mainframe formats :)
(though XML has xpath, and once the tools get more widely deployed and those of us who know regexes well get as comfortable with xpath, maybe it'll be less annoying)

Control characters like those continued in their physical functions well past the teletypes, of course. In the 80s and early 90s there were still plenty of printers that obeyed them, and of course a bunch of them moved on into pre-USB serial communications.