What key would be a good candidate as a default though? Imagine the memes for exiting vim if you needed a modifier to get into normal mode. Caps lock is truly a useless key and should be escape anyway.

As someone who cut their teeth on a sun "programmer" layout, I really need control to be in that position. I might try mapping the vestigial control key to escape though. Or maybe the hack that dtj1123 describes (tap is escape, hold is control), if I can pull that off on macos.