Hmmmm. I did tell you this was coming last year and you told me I was wrong IO.
My understanding of where the proposal is heading is for N Reg ops to continue but if the pilot is based in Europe over a certain period along with the aircraft the pilot will have to be dual licensed. How this is achieved is going to be an interesting question. Simple validation the same as the US and a foreign instrument test for IR pilots is possible but I suspect unlikely so more likely to be a subset of exams and a flight test. I don't believe there will be any difference between CPL or PPL holders.
This basically means that visiting airline aircraft and crews will be unchanged but those based in Europe under a flag of convenience will have to be dual qualified giving EASA 'oversight'. I think there will be something similar come out of the woodwork on maintenance as well.