On any module, there are two things that stand out as deal breakers for me:
- Flight Dynamics. It must “fly” as realistically as possible.
The rest is icing on the cake. The catch here is that 95% of people have no experience flying, much less flying military aircraft, so determining its realistic flight capabilities is kind of vague. This is were the actual pilot input would be awesome, but even then its still hit or miss. 2 examples that come to mind are the Gazelle and the MiG21. Both supposedly had real pilot input, more so on the MiG21, and both have had drastic flight model changes throughout its life cycle. The sound is one thing that can be easily verified.