A marked improvement over Age of Empires II: The Conquerors Expansion, AOE3 doesn't just add fancier graphics, they also added a number of new features to make the game less rock/paper/scissors. That shouldn't discount how satisfying the new animations are, with ship masts falling over and pieces of buildings flying in the air.

Your infantry units spread out nicely and block opponents from reaching ranged or artillery units behind them, something that was hard to accomplish in the previous game. Some units now have useful special abilities as well. There is also a new XP/Development Card mechanic that allows you to get free upgrades and units as you progress through the game, which breaks up the monotony of gathering resources and building units.

My only complaint is how cliche Act II of the scenario series turned out to be, but overall it seems like an even better RTS than its predecessor.