TAI does not have the expertise to upgrade to block 70 version. It would be performed in the US, unless PAF is able to push for a local upgrade at PAC, though that seems unlikely.
There is also little sense in upgrading really old airframes to the latest version, such as the Jordanian aircraft. If anything, upgrade just the latest block 52s and buy another squadron of new aircraft. Use the radars and other equipment to update the block 15ADFs to the same MLU standards basically as the current fleet.
That means any used aircraft could be early C/D variants or lower life (if any) block 15s. Looks like there are 201/37 A/B variants and 112/13 C/D variants in storage at the dessert, give or take.
I think even having a fleet of 45-60 block 70s, both upgraded and new, would be very potent and could lead the existing MLU birds in cooperative engagements. Don't think we need to or can afford to have every single aircraft upgraded.
Coupled with block IIIs, we are going to be in a very good position to work on AZM.