I don't see how this would work in the front. They need a low camera in the front to handle the same thing (giving the distance estimate to wall in front as you pull in). If they do add that low mounted camera (and let you see the feed), I would gladly give up ultrasonics for it though (as that would help with pulling in to curbs/concrete blocks in front, which the ultrasonic sensors are worthless for).
As others mentioned, the effect to autopark/summon probably isn't a big deal, it was horrible using ultrasonics, actually a lot better when they switched to Vision.