Only because Yaya wasn't there to dominate the middle.
Probably had something to do with it. Still though, I don't think Wilshere is the main problem. I'd agree with you guys that the formation isn't working out, both Ramsey and Ozil are in uncomfortable roles. I'd just play a 4-2-3-1, something like
----------------------Welbeck-----------------
---Cazorla/Podolski----Ozil---Alexis----------
---------------Wilshere-----Ramsey-----------
That's the default shape, but there would be a lot of movement involved, Wilshere and Ramsey could go up (though not both at the same time), Welbeck and Alexis can interchange, Ozil can roam out wide, etc. etc. And this seems much more defensively solid, Alexis and the other winger helping out on the wings, Ozil isn't burdened with serious defensive responsibility (because that really hurts his play), and Ramsey and Wilshere put in tackles in the middle. Arteta or Flamini can also play instead of Wilshere for extra solidity, but then Ramsey has to worry about going forward because leaving them stranded is asking for trouble on the counter.