No doubt, he's made his share of mistakes - the game against United is the last one where he got things terribly wrong.
But he seems to be getting a tune out of this squad despite dealing with a ton of injury problems. The decisions that went wrong are more on the board level than on the manager.
He's been making a lot of changes but it could well be a directive from the medical team since players didn't get pre-season. Let's wait and see how Arsenal goes. Unlike Barca who were playing their high line, Arsenal will have a mature and solid defense.