Here's a video:
http://www.youtube.com/watch?v=o4uP1YSTovs
Here's a summary of the combat system:
Thieves/assasins can backstab to get an insta-kill.
Melee fighters get the "Adrenaline-meter" which fills up as you fight, and when it's full, you can do a finishing move, KILLING ANY ENEMY, THIS IS THE WAY TO KILL BOSSES. Warriors can get 2 adrenaline meters, giving two potential finishers.
Mages have nice spells like ice on the ground making people fall when they walk over it, so much fun!
It has a kick. Very good for kicking enemies off ledges as you see in the video, and good to gain some breathing ground vs an enemy when you are an archer.
Disarming an enemy (if your a warrior) when they are stunned. Very good vs elite enemies like Vampire Knights.
Power attacks work like in oblivion, except you can hold it down and it wont automatically do the attack, making those "press-and-walk-back..OH-[censored]-MISS-'CAUSE-I-WALKED-TOO-BACK" moments disappear. And they are actaully effective now, you are in full control while making them and not doing a slow attack animation which renders you vulnerable to get god-like aim of the AI...-.-
Look into this Bethesda. Please. Not a combat system like in Oblivion. Make it more heroic & fun like in Dark Messiah.
Watch the whole video before commenting please...