The transmission does not have one set of clutches for even gears and one set for odd gears so that the gear is already pre-selected for practically instant shifts. The advantage it does have though is in torque handling capability and as with the M157 engines that generate a good amount of torque the upcoming M177 twin turbo V8's output has Mercedes sticking with their tried and true 7G Speedshift trans.
What is likely to happen is a similar scenario that the M156/M159 experienced in that the 63 AMG cars get the MCT trans whereas the higher end SLS AMG received a dual clutch gearbox. The M178 V8 that is based on the M177 but going into the AMG GT sports car that will battle the Porsche 911 will likely get a dual clutch box and have power sent to the rear wheels.
The C63 may then have all wheel drive just like the CLA45 AMG little brother and the E63 AMG big brother. The CLA though does route its power through a dual clutch transmission but this is due to having a motor half the size of what will be under the C63 AMG's hood. The lack of a dual clutch is disappointing but due to the displacement advantage on its rivals this will not be a major performance disadvantage.