Breaking Bad is a pretty good show, but I think it would be better if it was about a drug lord trying to become a high school teacher, instead of vice versa.
I'm not completely sure how everything else works in this universe. Gus should probably run the cafeteria and only be principal behind the scenes. Hank can be some sort of truancy officer. Tuco and the cousins run a smaller school in Mexico: they want Walt to teach there because he produces students who get over 99% scores on their finals.