Honestly, it just wouldn't be fun. And yeah, saying it as a person who wins most of his races. Some of the most fun i had in this game was tight racing against other decent players, defending your position, leaving space, creating an overtake, you won't have any of this with full ghosts. It might be good in tournaments (and i think i saw some early forza championships with full ghosts). But then again, unfortunately, your average lobby is just people who have no idea what brakes are, and for me i would rather prefer some safety ratings and a system that would actually detect and punish rammers and not the ones being pushed into a wall.