Wow, that's a close stance. (To me.) The movement as a whole seems a bit afluidic -- your legs kind of kick in out of the hole, then your back helps GM it up. I'm used to pretty different positioning, so I can't say much. How much of the lift do you push through your heels, and how much otherwise? Might be the stance, though.
Ever try box squats?
Ever try box squats?