(Sorry been traveling and sick)

in Karabiner you make a simple rebind "if terminal is active, let Cmd-C send something else"

That's great; we agree: "even if they are with something like Karabiner, 'My point is that it's always gonna be a little imperfect and maybe a lot of work'"

Everything else is you nakedly trying to score internet points instead of having an earnest discussion with me, which I would guess won't win you a lot of friends.