You see, imo, this is an example of a wrong lineup and too many changes.
If a standard defense is:
-- Alba-Pique-Masch-Alves
-- then, if you play Bartra as a Dc, you usually need Alves and Pique/Masch along him to cover his possible mistakes or any problems
-- Bartra paired with Montoya is asking for troubles
-- especially if even the 3rd guy is a new guy, Adriano
You have 3 new players in defense.
They didn't play together, they won't be synchronized, they will make some mistakes, they will be slightly confused during corners.
So, you have 3 changes in defense, Xavi in midfield as "a new guy", and Pedro in attack.
So, 5 new players, and with Pedro, Messi, Suarez, Messi needs to play in the middle, right?
If Messi plays on the right, he don't have Rakitic and Alves to link up with him, but only Rakitic. Also, he don't have Suaraz to drag the opponents away.
On the left, Neymar don't have Iniesta, but Xavi or Rakitic.
Montoya and Adriano are less useful in attack than Alves and Alba.
Xavi and Rakitic are two Cms, none of them is Amc like Iniesta or Rafinha.
In attack, we miss at least 1 from Msn trio, plus we need to change the system (Messi to the middle probably).
Too many changes, imo.
And most of the changes are "asking" from us to play the sterile, possession game, and this system is potentially asking for troubles.
So, Levante is an easy opponent, but imo, no need for 5 new players and for huge changes in out formation and tactics, since we have 6 days of rest after that match.