Mandibuzz should definately be moved up to at least A imo. It beats almost every atker in the game, it has defog + offers toxic which is one of the best cripple moves imo, especially on blue where heal bell/aromatherapy is barely used.
Also I don't understand why Chesnaught is so long down. H.a chesnaught completely walls gengar in pro unless it has icy wind. It's a strong tank whether you build it as impish or careful and even if drain punch is banned, it's still a better options than some of the pokemon you posted higher up in the list. I understand that it's pretty much impossible to get a good one right now, but it's still a viability list, and Chesnaught is definately more viable.