Recently, there's been some secret disagreement between Xavi Hernandez and the Barcelona president and that was the reason the club decided to sack him and announce his replacement immediately. I think it's a total disrespect to Xavi Hernandez by the club management to try convince him to stay back when they know they'll still sack him.
Here's what I think about the whole issue.
Barcelona is not in good place financially, so they knew that firing Xavi and hiring a new coach would be expensive for them, so I believe they were exploiting means to afford to let Xavi go and also afford a new top coach but they couldn't put all their eggs in one basket. They couldn't let Xavi go when they're not sure of a replacement or even sure if they can afford the replacement and afford Xavi's sacking, so what did they do? They convinced Xavi to stay. This way if they can't afford a new coach, Xavi stays, if they can afford a new coach, they fire Xavi. They had a fail safe and it turns out in the end Xavi got sacked and Flick was hired.
I feel bad for Xavi for been sacked in this way, but I can't blame Barcelona for doing what they did. Hard choices have to be made. They have to protect the interest of the club first before any other. Also, Xavi wasn't impressive this season so sacking him is not the worst of decisions.