I saw some videos a while back on AOE3, the guy was showing some of the gameplay, amazing to say the least... it has rag doll physics, buildings crumble causing damage/death to anyone it falls on. When the people are shot with a cannon, they get blown away like ragdolls off cliffs and into the water, its pretty amazing for an RTS.
Although its going to need a high-end graphics card to take full advantage of the features. The guy was saying that they added things into it which aren't even supported by current video cards.