I don't know if you've ever been in a hair-raising dogfight in the MiG-21, but the workload of switching between the weapon stations, switching between IR/SAR (which is also a "priority switch" IRL), flying your plane, keeping your enemy in sight, and watching your energy status is just ridiculous. And if they call it a simulation, they should in fact simulate the real plane. I would suggest to first finish a module and all its systems, before starting some Viggens and Tomcats and whatnot, but that's just my two cents.