I think with Trump in charge, this might be Pak's best chance to get upgrades to block 70 standard if Pak has the money...
...yes Trump is moody/erratic...but one thing u can't deny is he loves money flowing into the country. He gave no shits about KSA killing Kashogi just bcuz of billions of dollars worth of deals with KSA.
IMO same might apply to Pak buying Jordanian and other used F16s as long as US gets the contracts to upgrade them...again granted if Pak is gonna pay.
Trump will not be against money rolling into US economy. As for leverage he will only use the military/economic aid Pakistan gets from US. The only drawback I can see is that once Pak gets additional F16s and upgrades...the more leverage US will have for as long as Pak relies on those F16s(for repairs and spares).