Some recommendations I throught of.
Cobb can CHARGE - Cobb can move faster than the player in a straight line every so often, possibly used in a random direction even when he can't sense you.
Cobb can EAT - Cobb will regularly eat coal/food/rocks, potentially starving you or making the level impossible if you're not fast enough.
Cobb can FOCUS - Cobb begins pausing completely to increase his range of senses, but the increase only functions when he stops moving, like a slowly expanding circle.
Cobb can HIDE - Cobb becomes hidden in the darkness to the player just as the player is hidden to him.
Cobb can REMEMBER - Cobb will probe around where he previously sensed you for a while, even if he can't sense you such as if you're silent or in darkenss.
Cobb can SABOTAGE - Cobb can unflip breakers.
Cobb can SNEAK - Cobb becomes silent when he moves.
Cobb can STEAL - Cobb takes coal and food and moves it around, even taking coal off the conveyor belt.
Cobb can THINK - Cobb knows the entire layout of the map at all times, but doesn't automatically know where you are, and camps the position of coal and food, and as you run away he'll start trying to cut you off instead of just chasing where you've been.
Cobb can TRACK - Cobb will narrow down where you've been by sensing the path of where you've previously walked when he's near it, telling where you frequent and don't frequent to camp places you go to or guard places you haven't been.
Cobb can WEB - Cobb makes cobwebs that can trap the player temporarily.