The best would be a 3 regions map tbh.
In theory, perhaps, but its not going to happen in the present political climate. The immediate problem is reviving the Midwest and the Pacific. If we can accomplish that, even impermanently, with a four-region map, it's better than nothing.
To those shouting "three Regions or bust": would you really rather allow the Pacific and the Midwest to entirely collapse than accept an imperfect solution?
They would. If you look at who's shouting it and what they have to gain, you'll see why they're fighting so hard.