I don’t really see what a “Minecraft 2” can even offer that hasn’t been tried before. Obviously nothing can complete with the absolute magnitude, but the only things I can think of are focusing on a particular aspect and polishing it to a sheen - which has been done (Factorio is basically 2D “modded technical Minecraft” writ large, there’s that vagabondstory game, etc).
Someone could write a version of Minecraft that was much more performant or better architected but that doesn’t change the gameplay.