> I have never ever had bugs in my code from somehow having invalid Unicode code-points in my paths. 99% of the time, replacing '/' with '\' and handling drive letters gets you there. I realize certain classes of bugs could happen, but I'd rather take that risk, have a bug, and fix it, than burden the type system and libraries.

Lucky for you. I will think about you next time I have to fix one of these 1% pathname bugs you do not seem to be concerned about, which tend to happen all the time when your program is used by many people with many files (i.e. the case every developer hopes for)