There is however a compatibility issue: MySQL's Unicode support is limited to the 16-bit character range (basic multilingual plane), both for ucs2 and utf8 storage modes.
I can't believe you are seriously suggesting to allow this to limit us so badly that we would even have to close down an entire wiki (Gothic) and may possibly not be able to re-open it again in years. The same applies to high characters in article titles on Wikipedias such as Chinese that are actually active and may actually *need* them! If they are using them already, and they are working fine, and now you're taking it away from them, I don't think they are going to like you. I hope for strong opposition to such artificial limitations.
If MySQL's Unicode support is not up to the task, then DON'T USE IT.
Timwi