Let me quote what I wrote on the mailing list a few minutes ago:
You're missing the point of an RC. An RC is a release that we consider so stable and bug free, that the only way to identify possibly still hiding bugs, is to get the software installed and used by as many people as possible. If everybody just waits for the stable release, we can simply skip the RCs. That would decrease the quality of the final releases though.
BTW. upgrading a DokuWiki install is a matter of minutes.