What's in a (CentOS) version number?

Scientific Linux did a similar change (they versioned their -release package "6.0" instead "6") when RHEL 6 was released. The immediate effect was, that EPEL did not work as $releasever in the repository URLs was not substituted correctly.

There still are users out there for which providing a compatible rebuild of RHEL certainly is "as exciting as it once was".