Instead if asking this question, ad nauseum, can someone actually explain how they'd work then?
Trunks have been done on film, you can't ignore that just because it's Batman. The problem is that they are a dated concept, and even the comics recognize this. That being said, these same comics showed that trunks-less heroes didn't lose any of their recognizability or their iconography. So the argument that trunks are iconic for the superhero archetype doesn't hold well.
Also, that's a terrible example to defend the white-eyes argument. Spider-Man is one of the rare superheroes where it's absolutely necessary to have white-eyes since it's part of his costume design. However, you have characters where white-eyes didn't need to be applied: Batman, Wolverine, Mystique, to name a few. Did they lose anything just because they ditched the concept entirely/eye colour change? No. I have yet to hear a viable argument as to why white-eyes should be interpreted for film.