Also, i think that Iniesta can and should be used as a left winger when we shift the emphasis of attack from the right side to the left. Think about it, for a majority of the season we had used the left flank more often to channel our attack and Iniesta was absolutely amazing on the left wing and was involved in almost all plays. That was when Alves was injured/out of form. Now that Alves is supposedly "back in form" the attack has shifted to go down the right side again and therefore Iniesta is less involved and isolated on the left side. Montoya on the right not only allows Alba+Iniesta to really fuel the attack but it also frees up Pedro to attack much more often and make deadly runs instead of making up for Alves' inability to defend. It's a win win situation but it won't be used until the management finally gets tired of Alves and starts Montoya instead.
There is a hesitance to put the ball out to the wingers when isolated (except to Alves, I suppose), because of the lack of triangle passing options there, but when the center is being shut down, as Milan did, it's worth giving it to Iniesta who has proven he can dribble brilliantly along the goal-line. I was kinda shocked that Xavi didn't give Iniesta the ball in the moment shown below and back-passed instead. Xavi dribbled directly towards Iniesta for several seconds, and the gap remained open, yet Xavi never passed. Milan's right back certainly had his eye on Iniesta, but Iniesta could have still received the ball with plenty of time and space. He did get the ball a few seconds later from another Barça player, but by that time Milan had moved over and shut down the left side.
Maybe Xavi was waiting for Iniesta to make a move. Picture this: Iniesta accelerates laterally across towards Messi, Xavi passes to Iniesta, Iniesta quick touch to Messi, Iniesta breaks towards goal, Messi puts ball through to Iniesta between the RB and CB.