Interesting to hear about this design and it made me think about my Neptune. I have two way switches for the ceiling lights that have a two way switch near entry door and one in the bedroom. We use that two way switch feature very often. I also have a two way switch for the exterior bay lights..one in the tank bay and one just inside the entry door. The only other two way switch is for the dash radio..one power switch on the dash and one in the bedroom near the bed. I like being able to turn on the radio from the back after I wake up in the morning.
I agree that there should be at least one set of two way switches for the main lights.