It's quite interesting how a lot of people who were convinced that Ozil was a superfluous signing now don't see Mata as being similar.
For what it's worth, I think he's vital in ensuring you play a different style of football, but seemingly others are changing their tune.
Whether Dave will do that though is what some of us are questioning. I agree though, personally, I'd probably build a team around him as he's a very effective player.