I'm sure many of us are used to hacking xorg.conf with:
Option "DontZap" "1"
A change to the default just means that people who care in the other
direction need that same thing with s/1/0/ in their habits or
Neither of these is very satisfactory to me.
Where this really belongs in with the user "keyboard shortcuts"
settings, so each desktop user gets it the way they want it. Then really
nobody will care which way the default is, it's just a user preference.
(I understand why this is magically different from other keyboard config
things, but I don't really care what the preferences magic does
curtain if it makes it work.)
All that said, in my experience when C-M-DEL works, C-M-Fn also works to
switch VTs, with the same level of how-bad-the-session-is-borked
whether the X server magic hotkeys work. So, C-M-F3 and use the console
login to go kill it pretty much always works for the scenarios you are