Namely, Esc no longer closes any interface panels I have up (Guild/Character/Bag buttons, etc). It also does not open the menu that allows you to log out, exit, edit sound/video, etc.
I've deleted my WTF folders and exited the game. I've also tried to use my Priest's settings (where the Esc key works perfectly) for my Warrior, through the Bartender addon, but to no avail.
It's not the end of my world, but it is rather annoying.
Thanks for your help!