Are you kidding? Rommal would have surrendered in 1944 if he had his way.
As far as Dunkirk is concerned, has it escaped your notice that the British LOST that battle! In fact they lost 2 entire armies!
Once the allies committed 5 divisions to the D-Day assault there was no hope that the axis could hold.
It should be pointed out that Hitler never gave complete operational control to any of his generals if he could help it…. comes from being a paranoid megalomaniac. If we are going to talk about changing Hitlers personality we may as well consider that the war never happened.

The failure of the Germans to bring up reinforcements on D-day was irrelevant to the outcome of the battle. The vast air superiority and naval gun fire of the allies would have smashed them into mush. In fact, bringing up the reserves might have speeded up the fail of Paris and shortened the war. The Germans had no real chance to stop the invasion… they could only make it more bloody.
The only real blunder I see was the inability of the troops on Utah beach to communicate with the navy off shore. This did not effect the battles outcome, only cost American lives.