GNOME 3 was an upgrade to an already existing default. Cinnamon is being proposed as a new default. They aren't at the same level and while Linux Mint might have it, testing specifically the integration bits in Fedora is important and a number of things had to be patched even during the review of Cinnamon because Linux Mint and Fedora had different settings etc.
Keeping GNOME 2 as it is isn't really an option since it is dead upstream and no distribution has chosen to do that for precisely the same reason. Also there is zero "force" unless you consider any "default" as force since there are tons of options in http://spins.fedoraproject.org and one more is easily possible when someone volunteers to do the work.