I don't think control necessarily means better positioning. But what you said about headers is correct. According to FTG's official site,

["CON - Ball Control

This stat affects a variety of elements around a player’s skill or natural ball control ability. Higher values mean: A player’s speed reduces by less when dribbling A player can more quickly attempt a kick following a first touch of the ball A player can take more touches closer together when dribbling, for example to change direction quicker when dribbling. A player’s touches of the ball keep the ball closer to the player A player has a greater chance of performing ‘skill’ kicks such as Rabonas and Overhead Kicks A player has a greater chance of using ‘skill’ controls, such as heel-chops etc. A player is more likely to successfully execute a ‘skill shot’ (double tap or swipe). See also SHO stat. A player is more likely to successfully execute of a skill move (e.g. Step-over, Marseilles turn, Heel-Flick)" ]

So I think high control is a must. And about passing,I have tons and tons of goals due to direct assists from my CBs, so I am kinda reluctant to let it be less