Well, Dorian used what worked best for HIM. So, those heavy extensions probably worked at his favor, because he had great thighs. If we were talking about Coleman and his seesawing training motion style reps, his defensors would be saying the same thing:"yeah, look at him, his style of training works at his favor, who are you to judge, anyway!!!" , so, I wouldn't be so critical about Dorian's extensions, cuz it surely worked for him.
Besides that, I much prefer to emulate Dorian's style of training than Coleman's. Dorian is pretty solid and in control with his repetitions, even when employing those forced reps.