I understand that it's impossible to put VGA back into console mode in a
general and non-disgusting way.  But would it be possible to detect that
we're not in console mode, and do the non-ddb thing (dump and sync disks)
instead of dropping into a debugger that's unusable?  Currently the only
option seems to be a hardware reset, and I've toasted my file system a
couple of times because of this.

Mach had the same problem, but ddb was somehow able to read keystrokes.  So
you could type blindly and at least sync the disks and reboot.  Would this
be possible?