In the ideal world, you would set licensing standards at ICAO level and you would recognise ICAO licenses and convert them at national level for a fee, commensurate with the administrative work involved
The UK has recognised ICAO licences since the late 1940s, there is no fee and no work involved. Of course this doesn't suit the beaurocrats of Europe so it is about to end. AOPA are really only proposing that we go back to where we were pre JAA but lets not forget who dragged us into JAA in the first place, not the beaurocrats of Europe, it was not in their plan until AOPA put it there!.
Despite all the hype there is no such thing as a EASA PPL, only a series of National PPLs with an EASA sticker on them. Maybe the rest of the World should tell EASA that their licences will not be acceptable as EASA is not a member of ICAO; we could then forget them and continue with our National ICAO licences.