Three coaches have spent two and a half seasons trying to perpetuate an obsolete system... It's not like they have tried anything different when it comes to Cesc, except for Tata in the first half of this season...
Tata hasn't done anything in the 1st half of the season. Some peeps cling onto something that never happened ("Tata making Barca go away from possession until Xavi took over again"), just because of that Rayo Vallecano game. A tie in which Barca had equally low possession numbers under Tito because of the
state of the pitch coupled with Rayo's chaotic pressing and not because Tata was applying completely different tactics. Here is a whole article from a German tactic blog dedicated to that same tie under Vilanova from 2012:
http://spielverlagerung.de/2012/10/31/wie-rayo-dem-fc-barcelona-den-ballbesitz-streitig-machte/ (loosely translated: "How Rayo Vallecano tried to outfight Barcelona for possession"). We had between 52 and 55 % possession in that tie under Vilanova (depending how you count possession) and only 441 short passes compared to Rayo's 301. Tata himself said he was not going to touch Barca's style and repeatedly pointed out that the possession numbers under him were about the same as under Tito.
TL;DR: There was nothing "different". Just Messi's injury making us play differently with Cesc als false 9 where he had complete freedom in the final third.
