AII (Allama Iqbal International) is currently operating at 30% of it total capacity.So y u need to expand when u already have 70% capacity left?It was suppose to peak-out it's capacity in 2011 in the initial plan but considering the current ground realities i don't see that happening in next 10 years.
Also, the expansion plan was to only built 2 more satellites (as suggested in the original blue print design) along with minor expansion in the terminal building.That's about it.There wasn't any huge expansion plans for AII.
As for the New Islamabad International.well,the announcement was placed on the pressure of some renowned politician in mushraf's period who bought land besides the purposed airport site in pennies rate.they pressurized the govt. to announce it and those pigs became billionaires in matter or days.Also their are other technical issues related to the ground chemistry and wind directions as well.Because these things play major role in the direction of a runway.
How i know this,well my father was a high official in CAA,and participated during the construction of jinnah terminal karachi and Allama Iqbal international.And he was stationed in chaklala/Islamabad airport at the time of his retirement.