It'* not "bad engineering", and the rear wheel well isn't "in the way" accidentally. It'* a safety feature, and the rear wheel well was placed there on purpose allowing for a larger cabin and real back seats instead of the "back seats" of other cars that a little kid can't sit in...

You could potentially get the reas all the way down, but it would take a lot of custom cutting, custom glass, and you wouldn't be able to open the doors when the glass was down...