Actually, I think that minor differences between types are potentially more dangerous than major one.
E.G. if you swap from a C152 to a B747 you are not likely to forget which type you are in.
However, change a few bits and pieces around within the aircraft, and you are more likely to get caught out.
A good example of this is as follows. In the sim for our aircraft, the intercomm / radio PTT is a flip switch, spring loaded in both directions. But in the real aircraft only the radio PTT is sprung, the intercom switch stays in position until flipped back. This leads to radio cock ups which are potentially quite serious in the busy r/t environment of the London TMA. Its just one little switch, but new trainees learn the wrong motor skill in the sim.
CPB