Wow, that's news to me! How I've waited for Apple to do this. Karabiner-Elements does some shady stuff with the kernel and in my experience makes the machine a lot less reliable.

Sadly, that isn't as powerful as what our comment-ancestors do with Karabiner. Such an accessible and prominent key as Caps Lock is, IMHO, wasted if only used for ESC; using it both for Control when in combinations and ESC when alone makes the most sense.

I use Caps Lock for Cmd or Ctrl, depending on which keyboard I'm using, and <Leader><Leader> for Escape on Vim.

I don't know where I got this idea from, but I also use <Leader>w to exit to normal mode and save. It's so ingrained in me, that when I use other editors very often I have "Unexpected token" errors because of a ",w" in the middle of the code.

I use Keyboard Maestro for exactly this purpose. For the most part, it is great. However, it does just stop working every now and then, at least for me, which is mildly irritating.