A new Fedora developer mailing list thread is causing a bit of a polarized discussion and lots of "flaming" amongst users and other stakeholders: dnf even allows to uninstall RPM and systemd without warnings. This has been the most active Fedora-devel mailing list thread in a while, but unfortunately has degraded into personal attacks and other off-topic criticism.
The issue expressed that started the thread is that DNF's current handling will remove libraries with recursive dependencies -- to the point you can uninstall the complete OS, beyond the currently-running kernel. An example was given of a borked pcre package that ended up nuking most of the system.
Fedora's DNF has drawn lots of criticism, especially after some users found out DNF currently allows removing the running Linux kernel to the point of easily causing a non-working system if you're not typing carefully as root.
While DNF has drawn lots of criticism, it's also praised for its speed and modern architecture. DNF can be found on recent stable releases of Fedora Linux while the current plan is to make it the default in place of Yum for package management beginning with Fedora 22, which should premiere around H1'2015.