Weather animations for multiplayer are what I would like to see. I was just reading a post earlier talking on it a little bit, but if there was any chance that one of the Cry-(insert normal name here) people would communicate to the design team, a whole new post would have a better chance of recognition. The concept is you have different weather types: snowy, sunny, stormy etc.. and add a natural killing mechanism to it. For example, it's stormy? Lighting occasionally strikes somewhere on the map or a tornado may tear through a certain part. For snowy situations you could add less friction to surfaces to get an icy feel, and have snowflakes fall down that are capable of marking blood and foot-prints.
These things would be generated at random. Think about how cool it would be to wonder what kind of weather you may be playing in! I don't know about you guys, but it seems like an intriguing idea.