Melee is a tough way to go. I agree that it should probably be a little easier to hit, but I think you just had a run of bad luck on that one.
With that being said, you had the wrong traits for entering the UC. Here are some tips on the AoD.
It is very, very difficult to kill the AoD without being berzerk. In order to be berzerk you need to be playing an Angel of Berzerk challenge game or have at least one level of the Berzerk trait.
To kill the AoD without being berzerk, you still need all 3 levels of Brute. Even then you will need some healing (or lots of healing depending on your luck).
More tips on UC:
Blade killed the AoD, while being berserk and unarmed - the secret is in making him bleed, and then retreating while he loses HPs. But this requires shitloads of luck. Point is, if you see the AoD bleeding, consider not trying to hit him, but run until the bleeding stops, and then resume battering.
As said, it seems melee is rather unbalanced at the moment - you start out weak and somewhat luck-relient, and end up quite overpowered.