I must admit I was a bit skeptical because the biggest planned feature, the merge of the former Core with Extras, was not effective one month ago, after F7 test4 already come out (note in the past there were only three test releases); look what Will Woods, Fedora QA leader, said in a post on fedora-test list:
So, Koji is our new build system, which we set up after F7t4. You can
check it out here:
http://koji.fedoraproject.org/koji
(Yes, we replaced the entire build system for Fedora, just 3 weeks
before the release of F7. Yes, we are a little bit crazy. But we said we
would merge Core and Extras and get a release out by May 31 and by God,
we did.)