They have dated elements because they are dated. That's realistic. The movie outfit looks 26 years ahead of the time that it was supposed to have been designed. That's not realistic.Well why should they have dated elements? Why not just change it so they didn't have dated elements? Watchmen is supposed to be realistic and superheroes in campy, silly outfits isn't realistic.
These are super-heroes who haven't been active in nearly a decade, and were already a decade or two into their careers at that point. Dated outfits attest to that fact. Outfits that would have been futuristic even in the story's 1985 present make it look like these are cutting-edge heroes in their prime, when that's not what they're supposed to be.
I said this when the trailer came out. Glad to know that I'm not the only sane person here.