IMHO, one of the things missing from AH is smoke and wreckage. This may sound like a purely aesthetic concern. However, recently, I'm been doing a little work on my ground-pounding. I've studied the Eastern front quite a bit and, one sure giveaway to the location of the battle involving AFVs is the column of black smoke over each killed tank. It's a dead giveaway from both ground and air. Such a plume should last for a good long time - long after the hapless crew has been roasted.

I'd also like to see debris left at the airfields from past airstrikes - ideally, the kind of debris you can hit and from which you can receive damage.
Also, what are the odds that every corpse and every shot-down wreck can be allowed to live as debris on the forum floor, at least 'til tour end? It'd be cool if aircraft garbage/dead pilots turned into terrain feature yet retained colors.
I'm very American in the sense that I want to leave a cluttered battlefield.