Because i was thinking for blocking and attacking it should be directional IE sort of like mount and blade. Where you attack by slightly looking in a directing (left right up down) and your attack hits the enemy from that said direction and to block it would be the same way (except for shields it simply blocks), it makes the melee combat twitchy and extremely challenging for easier gameplay you could simply have an auto block that simply blocks the attack when you hit block instead of having to block in X direction. Also momentum affects damage as well so if your on a horse (ooo horse combat) and your galloping down an enemy you do x amount of damage calculation the weight and speed of the horse + other things.
Combine that with Movement based power attacks and killing moves your looking at some gooooood stuff sirs. Hell they could even do what M&B did and throw in a separate multiplayer.
http://www.youtube.com/watch?v=s7LbtHBP-Ro&feature=related
kind of gives you an idea of what i mean when im talking about M&B's melee system of course this is multiplayer and not how the AI fights. BTW SKIP TO 1:33, o and it's not in 1st person mode either normally people play multiplayer in 3rd person simply because u see more.
I give this idea b/c i found oblivions combat system to be boring.