The only way you can criticise MATS this year is by comparing him to previous seasons.. that I can understand. But even then, he never has bad games, there just have been some moments in the past year which were uncharacteristic to him where his judgement was off or he made a mistake. But that's the thing, people don't remember full games, they remember moments.
In reality though, Barça's defence this year was so bad that without MATS they would have been out the title race alltogether by February probably.