I was looking forward to the DH most as well. I know hatred is used for offensive skills and discipline for defensive skills, other than that not much as I was obviously not in a position to try the game out.
Yes, I forget the name of it. I used it for a while but it's a bit un-needed if you have vault. In fact, I think it was so lackluster that I didn't really understand any realy use for it because you can just attack at range and vault.