How exactly is Lesnar supposed to 'coach' and 'teach' others how to fight, when he does not know how to fight himself?
Not sure if you realize this or not, but it's a reality TV show that has one objective: get ratings to sell advertising. It's that simple. Brock will bring the ratings.
That said, Brock himself will be able to offer world class wrestling coaching. And, with wrestling being the foundation for most successful MMA fighters, this will be of great value to the contestants. As for BJJ, Muay Thai, boxing, etc., he will do what all the other prior coaches have done. He'll bring a team of assistant coaches in.
Hope that helps...