Speedyjay, do you realize you contradicted yourself?
You describe in real racing how the classes are divided by skill level and equipment. You compare a showroom stock to a all out race car. Yet you don't want RC to divide based on motor.
Despite what anyone tells you, stock was always supposed to be the beginner or entry level class. Somewhere along the way racers got lazy and decided to stay in stock rather than move up to mod. Pro racers, or I should say highly skilled racers, who stay in stock are stunting the growth of the hobby, especially in on road.
Why is nitro so popular? Because there is no slow class. Everyone has to run the fast class.
Why is off road so popular? Because it's more about driving than about motor tuning skills.