This is awesome! You should add ctrl+[ as an alias for escape as vim does. I've used that for a while now, and actually reaching up for escape feels unnatural now.
I was thinking the same thing. Not being able to use ctrl+[ actually made this game really really hard for me as my muscle memory screams in protests each time i want to exit insert mode.
Ctrl+[ isn't an alias for escape, it is escape on traditional terminals (and a whole lot of terminal emulators). It's useful to know this when using a keyboard that lacks an escape key.
And if you're one of those skeptics that thinks "but I sometimes use caps lock to type C_STYLE_CONSTANTS, and I need it!", there's a wonderful thing I call two-shift caps lock: you press both shift keys at the same time, and it toggles caps lock. Now you have your Shift keys, and your caps lock, and a key that really truly has no purpose. Now go forth into the world, and remap thy keyboard.
In GNOME: System → Preferences → Keyboard; Layouts; Options; Miscellaneous compatibility options → "Both Shift-Keys together toggle Caps Lock"
(You can also remap Caps Lock in this same dialog, so the change isn't just for Vim. It's under "Caps Lock key behavior". Also, having a compose key is awesome.)
