Wear on the inside of a tire usually indicates alignment issue. "Cupping" of a tire usually indicates a shock problem. Wear on both edges indicates routinely low tire pressure. Wear in the middle of a tire indicates routinely high tire pressure.
My ST is wearing its front tires on the inside as well. It goes in Wed. for new front tires & alignment. I can't complain, since this is the first alignment it has needed in about 130k miles.
Next up: front brakes (2nd time). Then new front tires & brakes on the Lightning. It's going to be an expensive summer!