The series only runs to about 1983 at most - currently Thirdwire are only concentrating on the pre 1983 era - and there have been no plans to change this so anything like an F-16C is a long way off if ever.
There are 2 F-16 models in development by modders here, one F-16C Block 25, and another model that might be used to represent modern versions such as the F-16E Block 60, and proposed Block 70 for India that was rejected recently.
There is actually an older F-16C model (7 years older )that you will find in the SF1 downloads - and you can convert it over - no cockpit was ever finished for it though.
In regards to lack of interest - people who flew Falcon 4 and its variants with HFFMs and avionics modelling are happy to fly something different in SF2 which could explain why its never been priority.