1st off, you all do know that the movie they're making in japan is going to go into great detail about kakashi's past? 2nd, let's assume that Kakashi got the sharingan from sugery...why would a scar result? They wouldn't need to open his head to put an eye into a socket! 2nd, my theory is, as we all know, Kakashi has only 1 original move, so he probably was one of the worst ninja's in the village, knowing probably mostly taijutsu, and his chidori. He was most likely in a fortunate, and odd posistion at one point in his life, and decided that to increase his strength, he'd just take the strongest tribe's eye, giving him the ability to learn all non-advanced bloodline moves. It'd make sence for Oro to want the eye, but he didn't.