I would agree with everything in the article except for the parts which suggest that forbidding punctuation in filenames is acceptable.
Filenames need to be usable for describing the contents of files. You sure as hell don't need newlines and tabs for that, but you certainly should be able to use the same punctuation you can use in a sentence - in English, that's !@#$%&()-:;"',.? but in other languages more characters may be needed (but they would be no different from any other non-ascii utf-8 character). I think the requirement that a filename can't start or end with certain characters is acceptable - you don't expect a sentence to start with most of them - but inside the string being forbidden from using them would be very constraining.