Correct, there would not be another way with this design. Without that third side window, they would have to remodel the shape of pretty much the entire car. And making the rear side window a window that can't be opened (like the 6er coupe for instance) would defy the purpose of the pillarless design.
If you squint it looks excellent
Series production of the new Mercedes-Benz E-Class Coupé has started at the Mercedes-Benz plant in Bremen, as part of a flexible system alongside the C-Class Coupé and C-Class Cabriolet.
Source: Mercedes-Benz
Disappointingly my C238 has a fingerprint - in - the rear window. This has caused the rear window to delaminate.
This was clearly a manufacturing fault when the window was manufactured.
It should have been picked up during quality control before leaving the factory, but alas, this did not happen.
I picked up this fault during the delivery inspection of my vehicle, however 8 months since I took delivery this issue has still
not been mutually resolved between the dealer from whom I purchased the car, Mercedes Benz Australia and myself.
Further the stitching on the dashboard is of very poor quality, this has also still not been resolved.
Finally, there are foreign fibres, of some type inside the sealed unit headlights, this also is still not resolved.
The dealer found other E Class vehicles in their dealership also had these foreign fibres inside the sealed unit headlights.
Additionally the customer service Manager, Mercedes Australia, has not contacted me for the last 10 weeks, this despite
me writing directly to the CEO, Horst Von Sanden, Mercedes Benz Australia. He did reply and advised the customer service
Manager would further investigate these faults.
This was 3 weeks ago yet no one has contacted me.