If it wasn't for India stepping in, the Bengalis themselves wouldn't have been able to take down the West Pakistan army and their cronies in such a short time. The Pak army doesn't face similar geographical challenges and restrictions in (West) Pakistan. As for KP, yes, it would be an absolute nightmare for the Pakistan Army if disgruntled people in KP start turning to the Afghan Taliban for material and moral support. This could become a reality if the Army decides to crack down on political dissidents in KP with full force, without regard for the life and honor of the victims, just like they're currently doing in Punjab.