I think there are pretty clear improvements in some areas of our game, namely intensity, mentality and control of the game. The way we matched Bayern for control of the ball would have been inconceivable the last few seasons, even when Messi was here.
I think people our forgetting how we used to get completely marginalized in these kinds of games, desperately holding out for some genius individual action. We used to be constatly two steps behind the game when the intensity was on. That is clearly not the case anymore and we owe that to Xavi.
On that basis alone, I think he deserves more time.
Offensively though we're completely bust, no ideas, no belief. If he doesn't make some fundamental changes to how we attack I don't see a way forward for him.