To be precise, if you have no xorg.conf, F11 will use nouveau automatically, assuming it's installed, which I think it should be (Matej, it was installed by default on previous releases, right - just not *used* by default?) If you have an xorg.conf remaining from a previous release which specifies a particular driver (nvidia or nv), that driver will continue to be used, F11 won't magically override your xorg.conf.
Atleast that's not what happened for me on a fresh F11 install with a Nvidia GeForce 6150. I got a 1024x768 stretched display with vesa. I had to manually create a new xorg.conf from the nouveau test day [1] and restart X. After that it worked fine.
This was a lxde only install that skipped firstboot if that is significant. Manually running system-config-display still came up with vesa at 1024x768 though.
[1] https://fedoraproject.org/w/uploads/d/d9/Xorg.conf.nouveau