You are going to buy cutting edge J35s, you are going to add further J10CPs which are themselves 4.5+ gen platforms, you are going to produce more JF blk3s which are 4.5 gen, and then on top of that the PFX program. Add the maintenance and weapon package cost of the above. After all said and done, do you really believe we will have spare dosh available for Blk-70s? Mind you, a platform, all of F16s, which we cannot customised according to our own needs and more importantly, inhouse weapons systems? And at what cost in literal terms?
F16s have been great servant to Pakistan, they still have utility as third tier line of defence , well behind the spearhead of j35/J10/JFblk3 , and of course can slap the rag tags in east at leisure, but in greater scheme of things, the bigger picture, I just dont see us increasing their numbers with newer models or even weapons packages. You are not going to slap IAF into submission with F16s, that will be done by the spearhead I mentioned.