I sort of agree with @willange on that one, if brevery debuffs cause opponent to spend CPs than they give you value, but at the same time it does nothing against abilities that don't require CPs, like Skaven auras, King's Ghouls battalion, ect. Whille a player still pays something for that, it's not CPs.
I'd like to see some changes made into IP and every similar ability, based on number of casualties, like when unit is reduced to 50% of it's starting strenght than those abilities make you count bravery roll as 1 instead of ignoring the check, once unit is reduced to 25% of it's starting strenght it can no longer benefit from those abilities.