Ok, Mehssi brought my attention to this thread due to the following video below from Sport's talk show called 100% BARÇA.
http://www.sport.es/es/tertulia-sport/
Led by Taltavull and attended by other Sport journalists among them Mascaró, Casanovas, San Antonio, Miguel etc.
They are basically saying that Lucho will leave mainly due to the stress of being a manager at Barça, the heavy criticism of him earlier this season by the media, his poor relation with Messi who commands the dressing room, that Anoeta was a point of no return for the trust between the squad and Lucho, that the squad in public makes it appear like everything is fine while there are disagreements, that the squad and Messi have made a deal with Lucho of them doing "their job" and leaving the disagreements aside for the common good of everyone, that Unzué has the respect and trust of the entire dressing room and that he might be lined up as his successor (this is what Miguel claims, the last one of the 3) etc. They also claim that none of the candidates want to have Lucho as their manager (they all have their own managers that they prefer to appoint, no names were mentioned though strangely enough), that the current board would be fine with Lucho leaving, that the relations between Lucho and the board were never the same again after Zubi was fired. Here we must remember that Zubi was basically the one that appointed Lucho and his biggest supporter. They also believe that this situation can't go on for another season and that Messi wants to be coached by a manager that he has a good relationship with. Mascaró also claims that the current board is looking for a substitute.
I might have missed some other smaller details but those are the main points.
In my eyes it's a bunch of hot air although it is not unlikely that he could leave. It really depends on him because I have no doubt, contrary to what they say, that the current board would love to retain Lucho. That and of course the relationship between Lucho and Messi. Is it really as bad as some rumors claim? I can't know but if that is the case he might very well leave.
I think that this is the main reason why they are saying that Lucho will leave this summer.