Commercial aircraft, like any other sort of industrial equipment, should not be designed in a vacuum. Designers need to understand the business environment as well. This includes both how the aircraft is to be financed and insured as well as how the aircraft is to be used to make money. After all, unless this aircraft can support a profitable business, it's a failure.
The basic business model, call it Model 1:
Air-shuttle bus to the airport.
Scheduled feeder routes.
Sky-diver aircraft. Should include smoke-jumpers, too, I suppose.
Deep rural combi. That is, both passengers and cargo on the same aircraft, on the same deck (legally).
Water-bomber. Especially appropriate for amphibian model. Non-amphibians might make a very nice foam bomber with a payload in excess of 4,000 lb.
Bush flying. Both land and amphibian models, with and without skis.
This is just off the top of my head. More detail to follow.