Dereks physique doesn't impress me. He's one of those guys who got on a shitload of drugs as a teenager and swoled out. Anyone could have done that. You could take an average built guy and put him on test and GH, have him do some mild workouts, and he'll look just as good. You give another guy who busts his ass in the gym the same drugs Derek took and he'd be a freak right now.
He's got no real mass, and resorted to using a lot of synthol to get his arms shoulders (and possibly pecs) a decent size. He's one of those guys who goes to the gym and gets pumped, without putting up any real weight, or without really busting his ass.
On a positive note - I think the most recent pics look the best. No, they aren't the biggest, but they hook as though you've chilled on the snythol and GH dosage. You actually look healthy there.