Only clowns could call Sampras a servebot. There's a reason he won 14 Slams, and players like Isner, Karlovic, and Rusedski won zero.
This times 100. He probably had one of the most accurate/powerful serves in tennis history, but still had the rest of his game to back it up.
He had a solid backhand, forehand, passing shot, slice shot, volley, and of course slam dunk volleys.
Isner has a good serve, and a good forehand, but that is basically it.