edit: I didnt get IC which would have improved the map, how does the DH map compare while leaving the original AoD 1.07 unmodded.
The DH map is vastly superior to the IC map (so is the vanilla map, come to think of it). Iron Cross adds stacks of provinces, which means theyr'e all really small, squashed up, and things look pretty messy once units get involved. Its really hard to hold a front, because of the sheer number of provinces you have divided you amies between to defend. Also really annoying is that none of the new provinces have IC or resources allocated, so all that extra terrirtory to fight over is essentially worthless.
DH adds provinces, but only a few hundred as opposed to the thousands in Iron Cross. However, they're added in intelligent places where it makes sense instead of just splattered everwhere the devs thought they could squeeze one in and still have the name be vaguely readable. All the new DH provinces have appropriate Infra, IC, and resources. The coastlines have also been redrawn to look more realistic, which makes it far more attractive to look at.
The DH maps killer feature though is that it uses a different method of calculating distance between provinces which accounts for the curvature of the earth, which leads to more realistic outcomes, particularly in the pacific. Unfortunately thats hardcoded, so the port to AoD will still have to use the vanillar calculations.