Udogie is a better natural defender than Porro- Ange just has him playing idiotic tactics.
Anyways I don't agree with your general point. I don't think Porro is even a "good" defender. He's very average, and if his offensive skills weren't so good, he'd look an awful lot like Reguilon.
No fullbacks will be a good defender in this system, how can you be? We basically play 2 at the back when we have the ball and the fullbacks have no chance of getting back.into.position if we lose the ball