I suspect the OP means east or whatever direction takes one directly towards the Reich.Isn't Brest in this scenario full of Germans from Normandy who have marched 'west immediately' into the Brittany peninsular?![]()
Though it's a good point - the degree of motorisation of the Allied forces means that without opposition they will rapidly overtake the retreating German forces. What happens then has the potential for a load of Grade 1 clusterfecks. Not to mention the Allies "treacherously" seizing the Siegfried line and then calmly disarming the Wehrmacht and SS forces as they arrive! Before proceeding on a nearly* unopposed march on Berlin.
* I'm assuming Hitler (or whoever is in charge) would transfer some loyal forces from the Eastern Front during this scenario.