Thanks for the reply.
I know of the film, with Stallone and Caine. I will have to disagree though, because my own idea for D4 would be that the Ducks themselves (with perhaps no more than 3 or 4 returning characters, none including Jackson's Charlie) would maybe be a periphery or equal presence to a group of insurgents - the latter group of characters having at least as much screen time.
In terms of tone, there'd be a complete change (which is okay because virtually all franchises feature inconsistent tones, e.g. Rocky and Terminator), which would be appropriate because it would retroactively make the previous movies feel more poignant, and demonstrate how reality itself is full of absurdities.
Essentially, the point of D4 would be to honour the legacy of the franchise, and to make a point of how reality itself can be utterly weird.
Specifically, a problem would be that if the state can be perceived as propaganda from an artistic point of view (just like how the Ducks can be seen as propaganda from an audience point of view), why should the Ducks be the opposite?
Why should the Ducks be important if the movie's self-awareness is existentialism, and reactionism. To be reactive to the previous ideology encompassing the previous three movies would seem to counter the behaviour of being endeared to the Ducks. Therefore perhaps the answer would have to be to incorporate that contradiction into the script.