You are correct. In the German Air Service throughout the war, the observer was in command of a recon plane and the bombardier was the commander of a bomber. The pilot was his chauffer. You can have non-com pilots and Leutnants in the pilot's seat, most often, it was the pilots.
If MvR was dissed for flying, it may also have to do witht he fact that a badged observer was regarded as a professional and efforts to play the chauffer was demeaning to the senior officers.
On the mission, I noted that the external models of the Aviatik C.I had the gunner in the rear. This is wrong. Gunner is in front on the BE2c, BE2e, Aviatik C.I and the FE2b.