I've read an interview with Rory Armes, vice-president of EA Canada, in the Portuguese games magazine "Megascore" (btw the best one in Portugal).
Rory Armes assumes that EA were more concerned with graphics, sound, etc...wich end up affecting the gameplay.
The AI system, passing system, and ball physics, were totally rewriten in just one year! Expect a lot of diferences here.
Some EA members from Europe went to Canada to give some of that knowledge about football, only present in the Europeans, to the game. The way of feel, think and play, the true football, according to Rory.
The ball will be more on the loose, that is a player when turning to suddently it will eventually loose the ball control, allowing it to be disputed by other players.
No more continuous sprinting players, the attribute system was changed so it became more real, it respects the weak and strong points of each player.
Free Kick system was also changed! WEEEEEE The new system resembles swing-o-meter of golf simulators (I don't know what that is...). It allows to determine with more accuracy the power of a shot.
At last no Portuguese league (again...), and probably no Euro 2004 by EA...they didn't like the sales of Euro 2000.
that's it, hope the English isn't very confusing