Xavi only did improving since he came. First in the league, now in CL. If you look at facts, that's what happened since he came. The team improved in mostly all areas, despite obvious problems, most of which aren't tied to Xavi himself, but the mess left behind by the previous board.
Now, of course, it's possible that the club adopts the position of: "thank you Xavi for doing a good job and getting us this far, now we think it's time for something different going forward", and elect another manager to make the next step.
That is the board's prerogative. But for that to work, you absolutely need to appoint a better manager than Xavi. You cannot name someone that will do less than Xavi was able to do with these players.
