In taking a composite view, the Centre must place greatest store by governability. And UP should be a special case and put on the fast track. Because its expanse makes it incongruous amongst states in hectic competition with each other.
Arguments are routinely made for and against small states, and there is enough experience to show for either side. But, for UP the deal should be clinched by the simple fact that political leaderships and administrations in smaller daughter states would be more easily made accountable.