I can tell that proper Unicode support is a reason to discounting a language/library if you're not a native English speaker and/or writing programs that have to be localized.
As a unrelated (to Python) example of the encoding nightmare: have you ever tried to import text from CSV files generated on different OS/locales in Excel that don't support Unicode-encoded CSV files? It can be made, sure... but, man, if it can be avoided... ;)
Having to work with 2 bytes languages (CJK typically) without proper Unicode support is much more of a hassle.
Proper unicode support is not even close to being a priority when it comes to dealing with Japanese text. No one would store important Japanese text in unicode. http://en.wikipedia.org/wiki/Han_unification#Unihan_.22abstr...
One size doesn't fit all.