* Not available until MySQL 5 migration complete
(Domas, what's the
status on testing?)
I did testing just for binary schema, I'm happy about application
support part, need some DBA-ish features to be merged though :)
Still, do note, that MySQL5 supports only BMP, and will cut strings if
there's anything beyond BMP in there.
* Collation use for sorting needs to be double-checked
to confirm it
wouldn't interfere with present uniqueness constraints
It will. If you want proper sorting, you'll end up using case-
insensitive unique constraints.
* Collations not available in MySQL for all languages
Well, we can ask people to describe those collations themselves, in
theory. In practice - too much work, and people would just have to use
generic UCI sorting rules.
* Multilingual sites possibly not well served by
Generic Unicode is good enough, usually.
It would also be possible to use a separate column for
sorting while using MySQL 4.1+'s native collations, if the uniqueness
constraints are a problem, but this is still dependent on rolling
upgrade from 4.0.
There's one more issue - if we go for utf8 columns, 255-character
limit is somewhat big. Are we going to reduce column sizes? What
problems would that bring upon us?