If the idea of having 240V outlets for imported European kitchen appliances does catch on you might be able to just do that
Imagine - first it's kitchen appliances, then space heaters in all other rooms, as those receptacles spread, grey imports of 230/240V entertainment equipment will go up... until lighting is the only 120V stuff left in the US
My way would have the lighting on 12V (and power the transformer from 240V).
Anyway, why force Schuko countries to switch to the French system? Polarization is most important with Edison base lights and those floor and table lamps are mostly double isolated and have Euro or contour plugs that can be reversed anyway. I think having both systems and phasing out the production of proprietary plugs (making all new plugs of the combined type, I think CEE 7/7 it is) is the best solution.
I don't see any reason why polarization is needed. I don't even see a need for a grounded conductor supplying current, either. Equipment would need to work that way to be safe on 240V in North America ... and reportedly some isolated remote parts of Norway, Spain, and Russia still on the pre-war 220/127 system with line-to-line power.
Manufacturers wishing to export to USA would need to make stuff work somehow on the 120/240 system we have over here. And this is not hard to do. Just don't design in any assumption of a grounded conductor. Make sure every insulation is suitable for a full 240V potential relative to anything else. Then with works fine on 230-0, 0-230, and 120-0-120. A UPS could be trickier since it would have to match the supply with its inverter output if there is any transition between systems.
Regarding the age old UK problem - what if one split up a 32 amp ring into two 16 amp radials by adding an MCB and disconnecting one part of the ring? Same amount of power available for the cost of two MCBs and French sockets can be used without any trouble.
That might work, but you would not have the liberty of putting the appliances that add up beyond 16 amps anywhere in the whole original ring. Just leave the ring connected, and put each end of the ring on a separate 16 amp MCB. If the circuit becomes open on one end while over current for one breaker, it trips.
