you mean il2-CoD tried it...and new planes still have it, even new functions like radiators cut-out and bypass in the 109.
It isn't really difficult is you create a generic system for fighter/bomber/biplane/whatevertype , not so closed-coded,that can be modified to suit each airplane.
A clickable cockpit is just a visualisation of the functionality of a system, and in il2 box, systems are very basic or even non existent anyway what links to the DM (like Seaserpent said). in BoX, airplanes are empty shells just like in 46, all DM effects are coded, there is no "interaction" with the model, unlike in CoD where the pathway of a bullet is calculated on the 3d model and tables with input data. If you shoot a bullet at a spit in CoD, the bullet trajectory is first calculated through the ballistic table, then, when it goes through a hitbox , let's say engine cover, bullet's path is recalculated with with angle, kinetic energy and type of material it's made of, a new trajectory is applied, if enough energy is available, the next part is the engine camhead, the soft will calculate if the available bullet energy is enough to go through it, if yes you got oil leak or worse depending on the type of the bullet....
Now, check the wildcat "squelet" images and guess why they bothered to model every part of the plane, my educated guess is that we'll have all the main systems available for the "pilot" and for the DM, which will be even more detailed than in CoD.