The question of airframe life left still is pivotal. Plus US would not let us buy from third party without gettung us to buy some new ones. It seems from PAFs buying in 2006 that at least 36 were commited for to get 28MLU plus kits. So how many do we have to buy to get the upgrades we want. Lastly the perrineal question of finances remains. Either case this makes a lot more sense than J10s.Agreed, but as more and more NATO F-35s are delivered I think we can expect to see even more Belgium, Dutch, Norwegian and Danish F-16s become available and they are all MLU'd to very similar standards to the PAF (Think PAF MLU maybe M4 tape), these would very easily fit into PAF, be very cheap and only require US end user approval.
As for the difference in infrastructure for the V, I am pretty sure it's just a AESA radar and new mission computer, not much of a new challenge for training or maintence