First I have to ask why would it be bad to have GFCIs in more locations?
I doubt that we will see a 200 amp GFCI main with 5 ma trip.
I believe many European homes are required to have a type of GFCI main but the trip level is higher than 5 ma.
Services and feeders larger than 1,000 amps and 150 volts to ground are required by the NEC to have ground fault protection however the trip level is often a few hundred amps or more. These GFP systems do not protect personal like GFCIs do.
