I found that in the quick ref guide. I can't quite seem to find the link where this is spelled out however. Does anyone have a link to a guide that shows how this was determined? Thanks.
10. On bosses, Improved Demoralizing Shout is not effective past 2 talent points. This is a significant change related to Attack Power values in Burning Crusade. However, in situations where Curse of Recklessness is applied to the creature, the full 5 points will be effective and will negate the additional Attack Power.