heh, imitating a real environment can never be adding complexity for complexity's sake :P Nature is FAR more complex than any system could accurately depict.
What you mean is complexity that doesn't itself add the experience of the gameplay. So it depends if you ask someone looking for non-complex environments in gameplay, or someone looking for as realistic/feasible an environment as possible.

On the former, I'd agree.

Maybe the solution is an option to toggle excessive complexity whether you're playing multiplayer or campaign (similar to the old days where 4-screen split reduced graphics quality; though that was to retain framerate, not for the main purpose of simpler gameplay environments)

But in campaign, I'm all for more realistic environments :)