From: Bristol, UK
I think you should not take 'political' too seriously. APs (in my book) reflect the overall hassle/inertia/effort of doing things. Just because a decision had to be relayed to Hitler would not necessarily make it slow/difficult... if you had a new wonder weapon, he would listen and decide instantly. But the 'system' for more usual things is slow and cumbersome. The fact that the Army commanders could make a decision, but didn't because they were nervous of it means that more APs would be used (in an ideal model) than a straight 'must go to Hitler but he will nod it through at the morning planning conference' type decision.
The German admin system as set up by the Nazis was astonishingly cumbersome and Byzantine... Hitler deliberately left some things vague and allowed his minions to fight over his favour. This means that they were incredibly protective of their own, tended to duplicate rather than work as a team, etc etc. The issues of the Allies working together have been documented, but on the whole had rather little effect on the war. The biggest (in WitW timeframe) was probably the debate on how to proceed in Sept 1944 (broad/narrow front). Ike fudged the choice due to the intrigue... you could model this by making depots very expensive for the Allies, but I do not think this is a good answer. You have to let the player make those mistakes on their own sometimes.
Whilst I would like to see how constraining the German AP figure is (not got in to playing Axis yet), I would be very anti any attempt to make the Germans fully flexible. They just weren't! Even the example of the single fortified zone earlier: for a start, the Corporal might ave a view (he was routinely down to divisional level by the late war, and his 'not one step back' edicts are famous. Then, the organisation that creates fortifications does not necessarily report to the local commander, or even the Army commander. Kesselring did as well as he did by ignoring Hitler, and riding rough shod. He got away with it by being succesful in a theatre that Hitler wasn't really watching. If Rommel had tried to remove some Atlantic Wall fortifications (as opposed to being horrified at how poor they were and increasing them) he would have had a huge fight on his hands....
I am a fan of not slavishly recreating history, but you have to watch balance... if the Germans were more flexible the Allies would have reacted and done different things. My favourite example of where people get it wrong is the Me262. 'If only the LW had got it in to service earlier it would have won the war'. Like heck. If it had been available in numbers sufficient to affect the 8th AF, the Allies would have countered... More emphesis on the Meteor, or more probably, more emphesis on finding their bases and camping LORCAP on them throughout daylight, more emphesis on fuel supplies, etc etc. The 262 might have paused the bombing for a bit, but would have been defeated just like the V1 (and to a lesser extent the V2, but had the ground advance not sorted that, the V2 would have been countered too). The Allies have such mind blowingly huge resources, they would have countered most things given a little time
I have a cunning plan, My Lord