that depend on who is the aggressor , what are they using ,
Pakistan Cant Afford Any Current Western Jets In Big Numbers , Cant Keep Hopes On Turkish bird as it will take minimum of 10 to 15 years , Going For Su 35 Will Be The Biggest Thing Pak Can do to piss off america but They can try to give some goodies which can stop pak from jumping on the other side ,
Possible is way is Make Thunder a capable Bird with Aesa and other EW , some changes in airframe and its material so it can hold its end against modern capable Birds , Add Few Squads of Viper and Valla It PAF can be a real decent potent force which will give Paf capability to go deep in enemy area on whole new level , j 31 Can be customised to our Need As same is being done With Thunder platform , We wont See thunder block 10 or 15 to The Natural process is Pakistan after Filling the Gap Will look at a new platform in to invest further for future