Iniesta is an amazing player, but him and Messi are very differen't. I don't see why you'd even bother comparing them. Messi has a much larger impact on the field than Iniesta. Although Iniesta can be a constant threat when he has the ball, and he sees a lot of it most of the time, Messi is way more influential. Messi can shift their entire team by moving a few steps or merely just getting the ball passed to him and passing it back quickly. Good players usually fade out when other teams realize how good they are and mark them out with multiple defenders; Messi finds a way around it and is still brilliant, that is what makes him great. Imagine if Messi wasn't marked as much as he is and had the space he had when he was younger?! Without Messi on the pitch regularly it'd be much more difficult for our midfield to function; Iniesta just doesn't carry as much an impact. Individually both are two very special, different players.