Instead of seeing it through a military or strategic prism, this deal of 8 F-16s is political in nature, sending a message that US is serious about engaging Pakistan.
You may be aware that leaked Wikileaks cables had quoted US diplomatic officials as having said that the “PAF is obsessed with F-16s” and the fighters have “an inflated symbolic importance in the public imagination”. PAF’s operations chief, Air Vice Marshal Khalid Chaudhry, was quoted in a cable of March 2006 as telling a visiting Pentagon official John Hillen to “ensure the F-16 deal has enough sweeteners to appeal to the public… (such as smart bombs and night vision)… but not to offer the PAF things it cannot afford.”
In a nutshell, this deal is nothing more than a political sop as these eight F-16s are not going to alter the military balance between India and Pakistan.
However, it needs to be mentioned that this is not a gift from the US. Pakistan will be paying in hard currency. And that is, $40-47 million a unit depending on the terms and conditions.