The problem with case-sensitive filesystems is - which locale's case-sensitivity rules does the filesystem use? Remember that some systems may have multiple us

The problem with case-sensitive filesystems is - which locale's case-sensitivity rules does the filesystem use? Remember that some systems may have multiple users (some may even have multiple simultaneous users) who use different locales. Or a single user might run different programs using different locales, e.g. if a program has a bad translation in their native language, they may prefer to run it with a different language that they also speak. A lot of computer systems only got rid of the problem of storing filenames in locale-specific character encodings (e.g. ISO-8859-*) relatively recently, by switching to a locale-neutral encoding (UTF-*/UCS-*). It would be nice if they could not repeat some of those problems with locale-specific filename matching rules. You could remove the problem of "requiring you to type the name with exact case" by having shells' autocomplete feature fix case issues. So you could type "vi foo<TAB>" and the autocomplete change that to "vi Foo.txt". That could have the advantage of also fixing combining character normalisation issues. And the question of "which locale's rules get used?" is easy - the locale of the shell doing the autocomplete.