Mister Fork,
I work in software QA. It seems to me that you are exagerating the difficulty quite a lot. Modifying the FM or DM of an existing aircraft should be a much, much smaller task than adding the art and code assets for an entirely new aircraft.
The biggest part of modifying the FM or DM would probably be the research part that Pyro would need to do, and Pyro is very busy as I understand it.
