This might still be a strategy to get him resigned, However, It is a good thing that he resigned the job than to get sacked by the Barcelona management board ,However, in my opinion Xavi stay at Barcelona hasn't yielded much of result so far, that is to try to bring back Barcelona to its usual glory, therefore it is right time they give another manager chance to try to fix things up with the Barcelona team.
Thinking that xavi hasn't done much enough for Barcelona would be undermining his efforts so far because I think he has done the best he could even with the situation of the team, he was still able to get them to win a trophy last season, he was also able to get them to qualify for several other elite leagues too which has helped them with some form of relevance this season too so he's done a whole lot actually.
I doubt if in the condition of Barcelona they will be able to get a coach in the quality of xavi and the resignation was actually the best option for him because it was becoming so much of a pressure on him meanwhile the management wasn't willing enough to do that which was needed and required of them to do so the tea. Will grow rather everything was blamed on their financial crisis which seem to never end because it's been almost two seasons now and they still have to battle with it such that it becomes a problem for them and affects their general productivity.
Barcelona has actually got a relatively good team they only needed a better atmosphere to strive a d not such filled with so much pressure where little is made available with expectations to making sure to achieve so much already from the little that has been made available to them . This is definitely going to affect the Players a d definitely reduce their chances of finishing well this season in the la Liga.