You’d be adding some players for some time. Everything they make you have to consider the initial flood and then the phase where people leave a bit later on.
3 versions of wow would make very, very small communities with what little they have left if the tinfoil hat wearers are correct on sub numbers (doubtful).
Still, there is only so many hours in the day and you’d have to pick and choose which version you’d wanna play that day and it would show overall between the 3 versions.