I've actually brought my stance in but just a lil bit. I found that I got better speed out of the hole when not going super wide.
My heels are now about 3" outside shoulder width.
When I used to go super wide, my hip flexors and adductors would be very sore the day after. The hip flexor would have the same kind of tight feeling that you get when you've sat down for like 5 hours in a row, like after a really long gaming session or when you step out of a long flight. I think you know what I mean. Anyway, I hate tight hip flexors.
Almost all of that has gone away now that I don't squat as wide, although I still go wider than most people. I've never had pains on the outside of the hip like some people get.
I can add that my hip mobility is pretty damn good. I can almost do a chinese split after some warmups and a stance out by the plates still feels too narrow for me when I pull sumo.
Hmm... seems like I have the same problem as you. I have a tendency to shift the weight forward on the way up on heavy squats. The bar path bows forward on the ascent. Not a huge problem and I can still reach depth fine, but it could become worse as I increase the weights. Maybe getting a pair of lifting shoes isn't a good idea after all, although I could still use them for front squats where I am lacking ankle dorsiflexion.