The OC needs to be in the booth to see first hand how the plays are developing so he can adjust his play calling to what the defense is doing in real time.
Head coaches, like Andy Reid, who call their own plays, have a OC level person in the booth doing the live analysis
Unfortunately, Alex is also the QB coach so he has a really big need to be on the sidelines in Trent's ear at all times he is off the field.
such is life when you cut staff to save a few bucks
Maybe Chuck Lester can serve as the skilled OC in the booth -