I was actually suggesting that the current Fedora is not actually short-term stable (because it accepts changes that aren't security/stability fixes and breaks your Thunderbird); the current policy is actually more like something between short-term stable and rawhide, where changes that are considered production-quality but are different in ways that may matter to users are accepted. My idea was that Fedora Rolling would be managed like Fedora N is now, and Fedora N would be more conservative, where switching to KDE 4.4 within a cycle wouldn't even be considered.