They don’t want to develop into the humor of BB. Jimmy is a pathetic character, he’s a guy who wanted more than he could really get, more money, more respect, and more influence on the world. It’s the story of how he starts finding those thing not by being a good lawyer, but by compromising. By reverting to the conman of old he gets everything he ever wanted, but it’s tainted, and we know from watching BB it’s the eventual source of his downfall. Not only does he lose himself to get everything he ever wanted, he loses that too.
More a "wages of sin" kind of story ...