Distance between Pakistan and Pakistan - Zero kms.
There was no B'desh before or during the war - it was Pakistan. Your failure to recognize them as your own country and your own people is what led to the war in the first place.
It was the ineptitude of your military that they failed to secure half the country. Distance had nothing to do with it - it was the flawed military doctrine that led to the defeat. The Pak army command, in all its unwisdom, declared the dotrine that "The deefence of the east lies in the west". They concentrated all their offensive power in the west, in the assumption that attacking India from another front would cause India to divert forces from the other front. However, that strategy failed miserably when the PA's formidable strike element comprising state of the art armour and infantry came to agrinding halt at Longewala and other places. Despite the huge force concentration of PA in the west, the IA was easily able to prevent PA from mounting any effective attacks. So don't make up excuses like distance (as if you didn't know about that before the war) after losing.
In fact the two wings of Pak could have been a big asset - if Pak had distributed forces judiciously, you could have forced India into a two front war, which is a big headache for any war planners. You could have mounted offenses on India from the east and west, had you not maintained such an idiotic doctrine.