I made a thread about it if you want to give it a look, the more we talk about it the better chance they will take it into account:
you’re right it might split the community a bit but It might be a good solution because as it is right now people that only like to play classic diablo( base game with no expansion) are able to enjoy the game without being forced to play LoD and I think most players will probably travel to the new realm once it will be interduced but they will have the option to play vanilla LoD if they choose too
you also made a good point about the player base being larger because of the region union, I have a feeling if they implement it, it would feel similar to how Classic, LoD and hardcore/softcore sections feel right now