Jul 20th 2010 5:13AM Zainir makes a good point. Looking up information elsewhere is a good idea. The first time I saw the new tree was on WoWHead and the way it's listed there makes perfect sense. The new ability says "Reduces the chance you'll be critically hit by melee attacks by 2%, and deals 97 Holy damage for each attack blocked." It makes no mention of a mana cost or cast time or ability duration at all.
Jul 20th 2010 4:53AM I obviously have no real idea, but the way I read it is that Holy Shield is no longer a spell but rather a passive ability. There is no mana cost or duration listed in the tool tip like other spells or abilities you have to cast manually. So i think you put talents into it and get the crit reduction and damage on block passively, all the time.