I've spent a lot of time researching this game and reading interviews from the dev team, here is some of what i know:
1. It has supports HDR and real-time shadows, it supports light blooming, the water has fresnal effect, it is a fully DX9 comliant engine, they want it to be the best.
2. It has havoc physics, when someone dies there is no animation, just ragdoll physics (HL2). cannons can hit ppl, cannons will rip holes in the sails of other ships, ships will blast holes in each other with deformation. When a building is hit it is NOT animated, it has deformation physics so bits of the building fall of realistically and collapse. If a tower falls over it CAN crush a villiger nearby. Units CAN fall of cliffs into the water, units CAN bounce of rooftops.
3. The entire AOE ecenomic structure is being remodeled, there will be a large focus on resources and economy.
4. the population limit will be drastically larger, you will have large amounts of units on the screen.
5. AOE 3 goes into the industrail age wich means the game will have: Ships bristling with cannons, ground cannons, wagons, rifles, guns, artillary.
6. Races include: american indians, french, spanish, english, and possibly english american.
7. it will be released in the second half of 2005. The game is "FEATURE COMPLETE" (quoted from the dev team), they have been working on it for "several years" (also quoted), they are just "OPTOMISING THE GAME ENGINE" (another quote).
THIS WILL ROCK!