Just a side note, my first AH games were,
"Stalingrad" and "Victory in the Pacific" at the age of 12, 28years ago. Still have both. Got addicted young, was by then reading as many WW2 books as my school libraries and my father bought the Time series of WW2 books, as well as another set written by the Swedes. Luckily I have been given both sets. I digress though.I think the retreat option is included already. In WW2 mass force was used to smash a holein a line. When an army went on the offensive, it was not to drive a unit backwards. It was an attempt to use a schwerepunkt to open a hole, allow units to stream through and surround. Only counter attacks were really used to push an enemy backoff of a ridge or maybe limited assaults to capture a better starting point(bridgeheads etc) for an offensive. Units at the point of attack usually would break and retreat only to be reformed some miles to the rear of the original front lines. IE, a cadre being rebuilt at a reduced cost, basically some replacements and new equipment.
All the other ideas have merit, hexes though would require a significant increase of unit density. This may change the game quiet drastically.
I have CEAW and was disturbed by the time comsuming drives that seems to put the Axis further and further behind schedule. I admit I did not play too many times though, could have been a noob problem.
As always just my 2 cents, wargamer to other wargamers......