Tenpenny, he is just so f*cking brutal and badass. On a related note, Steve Haines and Devin Weston are the absolute worst antagonists in the history of the series. They are just half-assed, annoying and not a threatening presence at all. Devin is like some early character you'd work for and then kill after a few missions, like Vlad for example. He is nowhere near threatening enough to be a main antagonist. Steve Haines? Just an annoying douchebag with a face you want to punch and and an irritating voice, who thinks he is the boss of everyone. I LOL'd when a Balla stuck it to him and he just took it like a bitch on that TV show. Tenpenny would take a piss on him.
Every antagonist in the past has done something unforgivable to the protag, they make you TRULY hate them. Steve Haines and Devin Weston never directly did anything to truly hurt the characters in any significant way. They are just an annoying presence that the trio has to deal with. They are just too bland to be the main antagonists of the game.