One of the things missing from 'realistic' games is specular reflection and friends. Little subtleties like that help. One of my favourite moments in the realism wars was that phase where everyone had to have 'realistic' water, and I remember logging into Morrowind for the first time. "The water does look nice, shimmery and shiny"... but it drew attention to the problem that nothing else in the game shined at all, it was all dead flat.