Yes, the numbers seem low. But at what RPMs are those numbers and what is the powerband like? What's the part throttle response like versus a smaller displacement lower cylinder engine making similar numbers? I bet you the response of this engine at part throttle is something that would open up some serious eyes. While the guy in his heavily boosted V6 making similar numbers is matting the pedal, this thing could probably do it at part throttle. It's not all about the peak numbers / full throttle runs.
My buddy has a 2003 W220 S600 with the 5.5L V12TT (493HP @ 5000 RPM, 590lb-ft @ 1800 RPM). It's what we call the rocket powered sofa. He had a guy in a Lambo try to go on him and he was keeping up neck and neck with him, even though this car is heavy as hell, all the while being quite comfortable. Makes me wonder how the S65 AMG feels with it's 6.0L V12TT (604HP @ 4800 RPM, 738lb-ft @ 2000RPM).
Even the part throttle response of this car is quite something. I'd only imagine that 11+ year newer engine technology makes it even better.