In the last few years some things got fixed about i18n - all sane distros use UTF-8 only, have fonts that cover most of the world preinstalled (including CJK), and contain packages with input method switch (scim).
What is needed now is:
- Instant feedback mechanism - when the translation sucks, the user should be able to correct it easily and submit it upstream as easily. This requires some serious changes in i18n infrastructure, but there is no way we'll be able to have quality localizations to hundreds of languages without instant feedback.
- Consistency of the translation (like not using "Skopiuj" form half of the time in place of "Kopiuj").
- Quality check - the translations are often plain wrong. Wrong is worse than unlocalized.
- Translation of everything. Everything. If something is not translated, it should be considered a serious bug.