Here's a few to start with that have cropped up in my mullings over your low-level airspace. Unlike the fanatic pushing this plan, I can't afford to come over there and look for myself... Please answer any or all of them??
Does the USA have any large areas where a pressurised twin would be out of communication for significant portions of the flight? How do you manage clearances & separation involving step-descents, DME standards or establishing definite passing outside VHF (and radar) coverage?
How do you establish definite passing in IMC between aircraft when one is not RNAV equipped and there is no radar or navaid coverage?
The model being contemplated by the above-mentioned fanatic includes Class E airspace between 4000 and 14,500 ft over all our capital cities, (the busiest would be a Class C airport over there). Is this still the model in place over there after 9-11?
Do you have a huge increase in workload when the weather is crappy?
Do you ever pass traffic in Class G or is separation applied regardless? Would you ever establish that a flight is clear of controlled airspace to avoid separating it?
Are you senior managers all back-stabbing @ss-holes like ours?