You wouldn't have a one eyed commercial pilot he wouldn't get a commercial medical here.
And to be honest Weaver is being talked about pretty much world wide. He is the face of N reg in alot of places.
Engineering wise,
I don't have anyway of knowing that but it wouldn't generate half as much fuss as doing the same with licenses. And you could set a start date and everything after that date would be deemed new and comply's with both and anything prior to that would have to go through the old system.
And they have already agreed in principle and the FAA is willing to reciprocate which is a huge tick in the box which licensing won't get. It helps having Airbus and Boeing having a common interest in that occuring.
In fact it might be quite a good way to encourage the retirement off alot of the old flying school junk out there.
To be honest the low powered single engine side of things I can't really get excited about it not being tested. The multi engined side of things you need to get regular practise single engine, the work load goes through the roof and it can bite your arse hard very quickly. I believe the high powered single can be a bit fiesty as well on the go around and you need a knack and practise for a nengine failure not to be a certain crash.