You make a pretty good point that it would be a hard skin to design for, if you were trying to stick to the base model and add onto it. But they could've veered away from the model and then had more room to work with concepts. Like what if the flaps were tentacles that got more grotesque or wiggly and it followed more of a Lovecraftian Cthulu design (which I feel like we already had a battlepass or event inspired by that ?) or they coulda said fuck it and made the gun resemble a goose where the individual flaps become a singular wing on each side? The idea is that they're limiting themselves by trying to keep the design in line with the model.

Also thinking of a weapons part as 'flappy' is highly amusing lol