The strategy was fine, but the execution was flawed. At the start of the war PAF was too timid with its attacks on Indian airbases, used WWII era bombs which did not explode in Agra, and did not continue with constant follow up attacks to hinder IAF runway repairs.And that weakness somehow is supposed to be our problem? Not a good excuse. No matter how underarmed you were, your strategy was of defence of East lies on the west, which just didn't work.
An offensive was meant to be launched into East Punjab but it never took place. In the Rajasthan offensive PAF was not employed which lead to the disaster that was Longewala. At the end of the war, India could not achieve a victory on the Western Front and gave territory in Kashmir and return all its gains in Pakistan.
East Pakistan was doomed to fall from the start unless Pakistan went full Nazi or caved into Mujib's demands for a state within a state - Bengal is further from Pakistan than Iraq. Fighting outnumbered 10:1 with the population of the most densely populated place on the planet against you will not end well in any circumstance.
If East Pakistan was friendly to Pakistan, the Indian military would face the same fierce and brutal militancy that non-Bengalis faced. Perhaps East Pakistan would be defensible in such a conventional scenario, and the defence of the East would really lie in the West.