You should also consider that a working GPS in a default aircraft also helps advertising Aerofly as a "serious" simulator which some people still don't seem to believe despite its achievements and brilliant flight physics. The moving map looks a little arcady to my taste and does not have a representation in the real world, while all other avionics are modeled to represent their real world counterpart. Maybe just add it to the Cessna and provide two options in the aircraft selection screen, C172 with GNS and C172 with standard moving map.
I also don't think that implementing the GNS makes the aircraft less accessible to casual or new players. If you create the flight plan in the Aerofly navigation menu you'll see it on the default GNS page and if you don't need to change something you don't even have to touch the GNS controls at all. In FSX and P3D I "followed the magenta line" for years without knowing anything about how the unit really works until I got more involved in the complexities of general aviation and tried to make sense of the different functions, which later led to me buying the Reality XP GNS 530 Addon and a hardware GNS unit for my homecockpit. But even if you just want to fly a route without worrying about real navigation the GNS lets you do that by just providing the path that you need to follow.
