Ursegor, I like how you failed to mention Cesc's two assists against Valencia, or his assist against Milan, or his goal against Sevilla, even though Milan and Sevilla both made it onto Iniesta's list. Regardless, the reason he doesn't really score or assist in big games is because he plays a different role there. Tata likes to have a 4 man midfield, and so he has Iniesta taking over the main attacking responsibilities, while Cesc helps stabilize the midfield, make sure there are no gaps, be a post for our more creative players, and put in an occasional tackle or foul if we need it. And if he does get an opportunity, he will play a dangerous pass, off the top of my head I can think of his (heavily deflected) pass to Messi against City at the Camp Nou for our first goal, and his ball to Alba to set up our "offside" goal at the Camp Nou. He's not going to get tons of goals and assists against big teams, but that doesn't make him useless.