Zoom levels is a fantastic addition to AoE. Being able to see (and hopefully) control units from such a vast view distance will make battles feel truly epic.
I suggest immersive sound be implemented based on zoom level.
Example: On closest zoom you may hear the clank of armor and shield, the sounds of boots marching over the brush, the hooves of fleeing deer pattering on the forest floor. The sound of a villager spearing fish in a stream.
On the second closest level you remove some of the ambient sound but hear the roar of battle or, back at home, the hustle of your village (farm animals, wood chopping, pickaxes chipping away at piles of stone).
Finally, as you zoom further away, the noise of the battle and your city subside. Only the heavy blows of catapult stones and ballistas as well as the hum of battle can be appreciated…A distant Wololo slips by on the breeze. The wind rushes through the clouds as you observe your armies looking down from the heavens.