I question the "Replay Bias" in which events closely ape OTL with these kinds of variations. That objection aside:
How does Rommel get started? US Involvement in WW1 is very minor and Rommel's exploits in WW1--escaping from Italian Captors, being a part of an elite infantry division--really can't be replicated.
Rommel had connections to the Third Reich's Hitler Youth program and ran a military academy--it would be unthinkable that US Rommel winds up teaching at West Point--that belongs to another big name in US History--Douglas MacArthur. (CalBear, ITTL, will buy you dinner for swapping McA with Rommel.)
He might gain great fame in the conduct of WW2 and rise to a rank of General, but this would not happen pre-1943 unless you REALLY monkied around with his story.
Due to the awesome points involved, I request that instead of replacing Ike with Rommel, you instead replace Dugout Doug with Rommel instead. I can barely imagine what the "Ocean Fox" will be able to do in this position.
