Ok here goes. We played a lot of games of Hearts of Iron 2 in the early stages of development to see where the game perfromed poorly. One of those was the post war map of Europe. It never looked good. Countries not reappearing when they should (my faourvite was a UK owned Hungary sitting in the middle of europe. Countries not properly reappearing when they should (e.g. chuncks of Norwar remaining part of the USSR). This is a limitation of the event system, trying to cover every possible permutation. However with our system of the countries remaining in place after conquest we cut down the number of permutations. We don't have to consider handing back ownership of the Netherland's provinces from all the possible countries that could end up with them at peace, they are already there owned by the Netherlands. Makes life a lot easier when it comes to setting up a surrender event for Germany.
A sound argument, and I agree that this system should fix a lot of the absurd territorial issues that come about as the result of a major nation surrendering.
However, I do agree with the statements regarding being able to release Ukraine, Belorussia, &c.
There needs to be a flexible system that allows for this, IMO.