Ah, but the thing is, MySQL will never (as far as we know/guess) release
5.2. MySQL 5.2, 6.0, 5.4, they've all been officially cancelled! Next version
currently is planned as MySQL 5.5. So we squeezed into the spare room :)

Then why not move away from their versioning numbers but always make sure they're greater than 5 or 6?  Almost like what Slackware did?
 
Arguably, our current numbering is a hack, although not without its merit. It
seems inevitable that sooner or later, if MariaDB and MySQL does not manage to
converge, some completely separate version numbering will be needed to

See above... :-)