I think people are a little hard on him. He was never the best player but he has upsides, and they could have been used better in this game. I think Laca was right to not drop too deep; he's good at putting in a shift but not so good at dictating play. With Özil picking up Jorginho (and doing it really well in the first half, though he disappeared in the second) we needed an outlet for the strikers though. We saw it when Iwobi finally came on - if Laca and Auba had had that support from the beginning there would have been more space for Laca to work in.
Ideally he or Auba would have shown up with an individual moment or two of brilliance, but I don't think that matters much in a game where you ship four goals and it mostly stopped at four because Chelsea stopped taking us seriously for the last 20 minutes. We put the strikers out there without any good plan for how to use them today. The tactic as usual seems to have been to hope for Kolasinac to supply most of the creativity, but he has been in Jenkinson mode for the last four months.