> I think the ideal situation would be to have a single
> Preference which lets you swap all Ctrl and Alt bindings.

This is extremely confusing and by no means "ideal". Believe me - I've tried
before to live with a complete Alt-Ctrl swap and it's just a mess. I'm all
in favour of making the keybindings more easily editable but not for just
blindly swapping modifier keys.

Cheers,
  - Andreas