thats because it is arcadey.i honestly dont see how it takes them so long to make mods for this game with the low level of graphics.
Because, if you notice, it will say model; Waffle, or Superfly- which means that ONE person did the 3d model. Then, ONE person does the internal texturing, and ONE person does the external texturing (who is normally a player). This game is a very small operation, they dont have dozens of people working on it like Il2 or CoD4.