the RCs should be 'somehow' predictable.. e.g. for the linux kernel you know it's monday morning (europe) when the next one drops in how many RCs we have mostly depends on how smooth things go.. so it is possible that the releasedate is not always 100% clear.. I guess it's up to the release maintainer to decide when things are mature enough, but maybe we need a few 'must haves' and a few 'this will delay' defined (means if, it's important enough that it will delay a release).. the