UTF-8 locales need to be supported throughout the distribution Programs that already work correctly in multi-byte locales using C library interfaces such as mblen(), mbtowc(), will work properly in UTF-8. Some other programs may have special-cased UTF-8 support though they don't support general multibyte locales.
*** Bug 66772 has been marked as a duplicate of this bug. ***
Showstopper issues are finished.
Some remaining UTF-8 issues: bug 68725, bug 71130, bug 71496, bug 73627, bug 78915
Closing. New bugs should be opened for where problems still remain.