I’m happy to hear that you enjoy the 1939, which my group spent so much time on yet likes to ignore every time I bring it up lately. All these new neutral rules have really helped to alleviate the problems of OOB neutral mayhem. Aside from alternate setups, modified neutrals is the only house rule my group consistently uses for just about every game.
I remember once we were playing with modified neutrals and three new players. While one of the amateurs was messing around with Japan, his opponent was conquering South America as ANZAC. Needless to say, these new players thoroughly enjoyed themselves and continue to promote modified neutrals for our gaming sessions.
We have a system here in which at the start of most games each person is allowed to pick two house rules he or she wants to play with. After everyone has made choices, we all vote on the selected house rules. Any house rules receiving votes more than half the number of players will be used in that session. Neutral changes almost always get implemented democratically.