I think its important to keep in mind that I think Pep and Tito originally crafted their tactics to suit specifically Xavi and Iniesta, even more so than Messi, at least from the beginning. Ronaldinho was relieved because of his influence on Messi and Pep knew he would not put in the work to play tiki-taka, but especially Deco was always blocking both of them and once Deco was sold to Chelsea, that is when the world really began to see just how brilliant Xaviniesta was.
The problem was Pep saw the monster he was creating in 2012. Less so with Iniesta but particularly with Xavi, he really can't compete any other way than by dominating possession, especially nowadays. He was never the fastest on the ball and he was never physically imposing, and those are qualities you need in a MF if you want to play more vertical football.
So I think particularly now since Xavi has pretty much been the captain since Puyol has retired, all of that puts Tata in an extremely precarious position in dealing with Xavi. Especially since I'm sure he was big on helping Tata "sip the tiki-taka kool-aid" and the amount of respect Xavi has in the dressing room and with the club in general, its just not a smart move to piss off a player like that, particularly being on the outside looking in.
Tata had a tough decision to make: stick to your guns by sticking with Cesc in the MF who suits your more direct approach more but ends up pissing off the captain of the team and get hounded by the press, all with the risk of it imploding later if Xavi decides to split the dressing room by protesting your principles. Or you go the safe route, stick with a system the players already know in favor of at least keeping the team somewhat united.
On top of that, if he does go with the latter, it conflicts with what he told to Cesc earlier in the season about him wanting to build the team around him so he can get the Cesc Fabregas of Arsenal. The former has the potential to divide the dressing room, a no win.
With all of this in mind, the tactics he deployed in the 2nd half of the season make a lot more sense. Iniesta on the LW and Neymar on the RW keeps both Cesc and Xavi in the lineup and perhaps he thought he could get the best of both worlds with something like this. IDK, it might have worked if Valdes and Pique had stayed healthy.
My conclusions from all of this showcase the biggest problem that stems all the way from the board to the players: they all seem to think its still 2010. If anything, a key lesson that you can learn from Pep's time here is that a good manager, in any sport not just football, creates a system that suits the players in the team. This isn't to suggest that I think tiki-taka is dead and that we should play heavy metal football like Dortmund, far from it.
Tiki-taka isn't the only way of playing attacking, attractive football. Our Barca B team still dominates possession against teams but they don't play identically to Pep's system. In all reality, right now on the squad and in the future, we will have players who are simply suited to more direct approaches. With a sturdier defense, we don't have to keep the ball 75% or more as the only way to keep a clean sheet and furthermore it will allow us to be more adventurous in our attacks.
We don't need to revamp our entire club philosophy just because we have faltered recently, particularly when its clear as day that when this team is in full force, its still untouchable. All we need to do is make some adjustments and tweaks to our tactics and shape that suits the players we have on the team. If Xavi can't realize that the club is bigger than he is, he needs a wake up call and I think Luis Enrique won't be afraid to do so since he is a club legend himself.
My only gripe with Tata in the end is that he didn't stick to his convictions, particularly when the results were supporting him, regardless of the Rayo fallout. With a semi-competent board supporting him instead of alienating him, and less distractions outside of the pitch, Tata probably would have fared a lot better and the amount of humility and respect he has shown throughout this entire season is truly testament to his qualities as a gentleman. A dying breed in football.
I sincerely wish him the best after this season and I hope another club takes a chance on him. He is sure to have learned a lot from this experience and I think he should consider staying and coaching somewhere in Europe if he is up to it. A club like Inter where he has a rich billionaire that can get him the players he wants with lower expectations would suit him well. He could truly manage the team and get them to play the way he wants them to without the pressure of a playing tradition like at Barca, and I think with a situation like that, he could flourish.
He deserves to walk out of the club with his head held high. I honestly think he tried the best he could in an impossibly difficult situation.