I believe Kishimoto meant pain and Itachi to be equal in terms of power not one greater than the other. I think Kishimoto wanted obstacles in place for the main characters that were of equal diffiuclty. later when pain and itachi were together walking they claimed they could take over the world. I believe them to be two halves of a whole. Pain being the crazy sweeper, carrying out long ranged attacks insane destructive. and Itachi for precise and refined attacks coupled with insane speed. Idk what do you all think? this isn't a versus thread but a discussion fyi.