I have. Fired up the terminal and started Vim. 5 minutes later I was convinced that my next computer will probably come with Windows. Really sad, too. I don't have to blow away the OS to get a decent experience on a Mac.
I am no longer a Mac user, but might I suggest remapping the escape key to another, it really saves a ton of time. Personally I use "hh", which makes some vim users cringe, but let me tell you, it's so much faster than escape.
Caps lock seems like an obvious one, no? It's on the home row and I've never used it in my entire typing life (apart from to turn it off if I turn it on by accident).
Oh no. We're not going there. My hands are not so small, and I've got the rattlesnake-like "hit esc" action down. Thinking about the command keys again sounds like a great way to discard all of my productivity for about three weeks.
Fair enough, but I've heard similar reasoning espoused from other vim users who were reluctant to transition away from arrow keys. Perhaps you might find the productivity dip worth it in the long run, but I am not unsympathetic to the cost of shaking the routine up.
I can vouch for this. It's much faster for me to hit "jk" (my preferred mapping for escape) than it is to hit the Escape key. And given how frequently you need Escape in Vim, the time adds up really fast. It's also just a lot more comfortable, because my hands can remain on the home row.
I've had problems remapping basic functionality keys in the past. I switched ':' and ';' for instance, it works great in vim when my profile is loaded but leads to a lot of mistakes in other environments, either machines or one of the million emulators.