When you're at the top of your game, you have the luxury of making evolutionary improvements instead of radical changes. The Mercedes-Benz S-class has been the best-selling car in its class for decades because it looks good (unlike the BMW 7-series), it has a reputation for quality (unlike Cadillac and Jaguar), and the three-pointed star on its hood is a beacon of status and wealth (unlike Audi). The outgoing S-class, codenamed W220, wasn't the best car in class to drive (stand up BMW 7-series), and its interior wasn't spectacular (that would be the Audi A8). But it did everything pretty well and nothing particularly badly.