Basic question: Is there any mad scientist madder than Moreau?
So far as I've seen, not really.
Frankenstein wanted to preserve and create life.
Emmet Brown wanted to learn what happened in the past and prevent the problems of the future.
Dr. Evo feared death.
But Moreau? Moreau wanted to make animals more like people. He's like a sadistic, imperialistic Walt Disney. The man was GONE.
I think the Brando's super- crazy persona was the best route for Moreau, actually.