To fix number 4, go into the regional settings (assuming you are using XP), and set the "Language for Non-Unicode Programs" to Japanese to be able to play Japanese-named files, Chinese to be able to play Chinese-named files, and so on in that matter.
I too would like it to be able to support all codesets, therefore I support the integration of Unicode (which is already built into Windows XP everywhere else).
If you like, you could post in the other thread for Unicode support.
http://forum.bsplayer.org/viewtopic.php?t=4961
My theory is, if we make a big enough thread, they'll put it in.