I'll repeat what I said before:
The rumblings of Pakistan going into deals with Turkish won't necessarily be a good thing because of the extra time it will take to get there. For now there is a direct service to ISB which takes around 7.30 hours, with a transit in IST then the whole flight could take around 10 hours or more. Not the way forward me thinks.
The only way this route could work is if the fare structures were low and TK/PIA went head to head with EK. if not then EK will have the monopoly on the route and as I said before maybe BHX will get it's 3rd service.
I remember using PIA'S PEW route back in 2004/5. It took 7.45 for the non stop flight, after they stopped it it took 20 hours via DXB and a lot more money.