If you run Scourge you don't get the attacks like you would out of Cad but Scourge does the damage that Cad wouldn't do. Also you can use the other points for someone like Arden Lyn. Activations is key in a squad like this and the Vader you want to run just too high cost to run effectively with Cad and Thrawn. But to each his own, I just thought I would tell you my opinion in the matter.