Combat Aspect
With the larger maps, it became necessary to speed units up. They don't move unrealistically fast, but the difference is quite marked when compared to the original two Total War titles. Walking infantry move about as fast as the older infantry ran. Yet, despite this, there's no sense of awkwardness to the gameplay.
The move to 3D has also permitted and necessitated some changes in gameplay mechanics. For starters, individual characters on the screen are now truly independent. They try to remain in formation of course, but aren't as tight as they used to be. This is most evident on three occasions - a rout, when undisciplined formations charge, and during a cavalry charge. However, the move to 3D means that units can't respond instantly - they must go through their animations. So if you order them to pull back, they don't just turn around instantly and go the other way, they must rotate. This has the unintended but very welcome effect of seemingly delaying battle orders. Combined with the faster pace of play, a player can't immediately adjust his forces to counter his opponent's moves - it is possible and quite likely to make mistakes now if you don't anticipate correctly.
Speaking of animations, the cavalry charges are most spectacular. Our equestrian friends don't just run up to a group of infantry and stand there, hacking it out hand-to-hand. They rush in, smashing the footmen down and knocking them aside - blasting right through an entire formation and then cutting down the survivors. Elephant charges are even more impressive, trampling men and knocking them about like nothing but soccer balls. The designers at Creative Assembly are looking to recreate the power of Shogun's cavalry, rather than the toned-down version present in Medieval. From what we saw, they're well on their way to achieving this.
In the build we played, archers were severely overpowered due to a bug that had just been solved, ironically enough. However, despite the power of cavalry and archers, it was clear that victory still required a balanced attack. At the core, the game is still, in the designers' words, paper-rock-scissors. Each unit has a counter or two, and a unit that it's devastating against. These counters are compounded by the various tactical considerations. Spearmen are devastating against cavalry, but not even the toughest hoplites are going to stand up to a charge from the rear.