Tested the latest NVIDIA driver – 352.63 – and it is OK with Kernel 4.3, and with the Fedora 23 version of the xorg server..

The only other ‘broken’ Fedora 23 items I have encountered are ffmpegthumbs and Samba..    I downgraded to the FC22 version of Samba

# dnf --showduplicates --allowerasing --releasever=22 downgrade samba*

….and  – after a lot of unsuccessful testing and re-compiling – found a working version of ffmpegthumbs here:  http://phobeus.de/tmp/kdesig/

So, my /etc/dnf/dnf.conf has the appropriate excludes, for the time being:

[main]
gpgcheck=1
installonly_limit=3
clean_requirements_on_remove=true
exclude=ffmpegthumbs* samba*

Robert Gadsdon.  November 16, 2015.