Hmm, BHX has a track record of attaining airlines which either serve none, or one other, UK destination. Armavia, Uzbekistan, Turkmenistan and Air India are examples.
Even though Shaheen Air was indeed a rumour, I can see them starting a UK destination in the future with their new A330s. Whether BHX should/would be that destination, I'm not entirely sure, it all depends on how well the PIA flights are performing. Anyone have any statistics for those flights?