If you want real blocking you would need a more physics driven engine.
Because:
If I were to come down on you with a Warhammer and you blocked, would you feel any of that impact? Yes you feel all of it and might even break your arm.
For that there would have to be different damage types, like blunt damage, piercing damage, and cutting damage.
Each blow would be divided into %'s of each damage. A sword, that is thrusting, might be 80% piercing 10% cutting and 10% blunt. If a shield were there, it would negate the piercing (unless it was enough to pierce the shield) and cutting damages, but transfer the blunt damage, which would be minimal.
A warhammer would be 100% blunt, a shield would transfer it.
And cutting damage is needed because chainmail would stop cutting damage, but transfer blunt (maybe absorb some of it for lighter armors, like fur) and piercing would penetrate it.
A system like this would be cool, to me at least, and far more realistic. But who wants to code all of that?
Although it could be done in a much less complex way, but thats no fun.
At least thats what I think should be done, but TES will never do it, its too far from the series.