That proposal to divide airspace into (essentially) known and unknown categories has
AFAIK been dropped. It would be contrary to ICAO, etc.
Obviously it is still possible to revise airspace but retain the existing classes A-G. I have no idea whether this is on the cards.
But the big differences in the way airspace is used around Europe is at the root of this issue - the UK has lots of Class G and practically everything else is Class A. Class D is operated as Class A, more or less. The IMCR works well in the UK; it would not work in say Belgium.