The issue is that we need air defense and not massive ground attack or deep strike. So do we need big planes and risk pilots or tracking by enemy?
In the past one needed two engines and two pilots to have decent range, weaponload and big radar with good avionics. Now with netcentric warfare and much smaller sensors the goal is no longer huge planes. Besides that at the moment passing the border is a jump in the middle of the minefield! Both sides have tons of radars, sams etc...
I do not think J16 fits in Pakistani profile. Pakistan moved to asymmetric warfare. Most deep strike work is moved to BM/CM or smart weapons. Even on the border they moved to small nuclear bombs (Nasr)...
One thing that does fit is the J31. Till then we will see nothing else besides... JF17, FC20. Trust me.