How much would you be willing to pay for the service? At the moment light aircraft pay nothing, yet cause the most grief when INCAS because they have poor performance i.e. they are in the way for much longer, take longer to vacate levels etc.
Workload rises way out of proportion when you add a puddle jumper to the equation.
Maybe set rates at how complex an aircraft makes things by being in the airspace.... but that would see a pilot of a C152 paying much more than a 777!!