You couldn't let Davie Stone ride a GP bike. He'd crush the field by such a large margin that all of the current riders would just wilt. They'd give up and go home in desperation and embarrassment. It would completely destroy roadracing.
EM's ride on the GSVR definitely had steel rotors, not ceramic. Even Hayden has repeatedly said that is the hardest thing to get used to on a GP bike. I liken it to the down-force in F1 racing. You can negotiate a given turn at 75 mph on tire grip alone, or at 110 with the additional down-force created by the increased speed, but between there is a dead-zone for traction. you're out-driving the tires, without gaining enough help from down-force. Sort of the same for ceramic brakes. You can pussy-foot around on them and brake at the 500 ft mark and still make the corner no problem, or you can do it right and wait until the 150 marker, and keep enough heat in them that they work that way for every stop, but between those two brake markers is another dead-zone, where you've got too little stopping distance, and not enough heat. That said, with notes from a pro team (i.e. they tell you your braking point), and a WERA expert who can convince himself to trust them, I think within 8 seconds is possible. not easy, by any means, but possible.