Even though I have a 2017 MBP 13" with the Escape key, I still use Ctrl-[ to change modes in Vim. I'm not a fan of the Touch Bar, but it probably wouldn't interfere with my Vim workflow.
I do, but not because there's anything wrong with that remapping. It's that I already have Caps Lock mapped to Ctrl/Command, as in UNIX or Sun workstation keyboard style. So, when I press `Ctrl-[` only my right pinky leaves the home row, and it's hardly much of a move, since the `[` key is above and to the right of `;`.