if we have a time machine then yes. In fact, it shouldn't even be an option. UTF-8 period. Always.
But alas, we do not and someone will plug in a memory card or USB drive with some FAT formatted drive and your nice universe crumbles before you.
But alas, we do not and someone will plug in a memory card or USB drive with some FAT formatted drive and your nice universe crumbles before you.
The lesson of text is clear: text needs to have a defined charset. Filesystem names are absolutely textual (listing a directory for human display is one of the most common operations). If it's not UTF-8, then what is it? How is the application supposed to figure it out? (Automatic encoding detection is flaky in the best of times, but with the lengths of typical filenames, it is almost impossible to be reliable). The reality is that most applications already assume that filesystem names are UTF-8, and non-UTF-8 names break them.
We are at a stage in Unicode penetration that I think it is reasonable to treat a filesystem that has non-UTF-8 filenames as a problem that needs to be solved with some kind of repair tool like fsck, not something that every application is supposed to worry about.