So out of 100, maybe I would say the difference between Prime Messi and Iniesta was this.
Dribbling: Messi 100, Iniesta 98
Ball Control: Messi 99, Iniesta 100
Overall Technique: Messi 100, Iniesta 100
First Touch: Messi 97, Iniesta 98
Obviously Messi is way better at shooting, the final ball, and is far more consistent with all of his skills and abilities. He's now also better at being a tempo controller than Prime Iniesta.
I love Iniesta so much, he was my favorite player in the world. But he is not 'better' than Messi, not even in dribbling in his prime, because he didn't do it as consistently as Messi. Maybe he had the 'same' level, or ability, or pure dribbling technique, but part of Messi's genius is how he pulls it off over, and over, and over, and over again.
Remember, Iniesta is the Illusionista. He creates the illusions that he is better than fucking
everyone when he is pulling off pure art like that. Sometimes you even forget he has the best player in the world next to him.