That depends on which rankings you're talking about. Obviously it won't affect single-target at all, but it's a pretty radical nerf to AoE performance where comparable AoE specs received no nerfs or small nerfs. One thing I'm very concerned about is how badly this is going to affect my performance in challenge modes, particularly ones where I don't have Dark Simulacrum spells to abuse. 33% less Blood Boil damage in a CM is a very, very big deal.