Starting out in 2nd is not just limited to M-B vehicles built in the era of fluid coupling auto-boxes. My W124 300D also takes off normally in 2nd. Like my Pagoda, it will take off in 1st if the accelerator pedal is floored but, face it, how often is it really necessary to floor the accelerator when pulling away from rest? Quite apart from generating sharp looks and words from "she who must be obeyed" (who thought we were just going out for a nice leisurely ride) the full throttle shift from 1st to 2nd puts unnecessary stress on motor mounts, transmission mounts and flex discs.
Now, lets examine the real reason why the 1st gear is so low in relatively heavy vehicles with relatively small displacement engines: It's about being able to move from rest on steep grades without rolling back or stalling. In Britain, there has been a motor vehicle test on the books for over a century that prescribes that any vehicle registered in the UK must be capable of starting off in low gear on the steepest section of Ffordd Pen Lech in Harlech, Snowdonia, Wales without stalling or rolling back. Ffordd Pen Lech is the lane up to Harlech Castle and is the steepest signed, public, sealed road in the UK, with a posted 40% grade. (Another test prescribes that the handbrake alone must hold a vehicle in place on this same section of road.)