i don't think that this is the main reason for not allowing some more characters. if you allow backslash as an escaping character in pd, you will get into serious problems when windows users try to load "C:\files\patch.pd", or should it read "C:\Program\ Files\patch.pd" ? what does this mean ??
Hmm, i don't understand... what's the problem about an encoding "C:\Program\ Files\patch.pd", or as used in pd "C:/Program\ Files/patch.pd" ? It's not only about filenames... as symbols can hold all possible characters, we (or me at least) would also like to enter it in the patch editor. There are numerous applications (like a text-based composition that i'm working on now) that would profit from this possibility.
and windowsers will immediately start using backslash as directory delimiter, while unixers will use it as escape.
Since i use Windows, OSX and Linux, also with mounted volumes across system-boundaries, i don't see why others shouldn't be able to handle that.
I really can't think of why \ should be dropped if it's possible to use it as _the_ common-place escape character. Maybe someone can enlighten me about Miller's possible reasons to do so. But there's always the devel branch where such things can be tried out...
best greetings, Thomas