Might sound strange but I always feel you need your central midfielders to have that bit of character or edge. To grab hold off a game, to get a bit peeved off and kick start a team performance off. It's a hugely influential area of the pitch and he's just a bit too timid and on the edges for me.
Yes, it looks pretty, yes, it's great when we're cruising and the passes are being sprayed about, but it's more about the times when those things aren't happening.
As said above, when you need a drive and someone to get things going.
Maybe that might come as he settles, but I'd like him to have more meaningful influence to be considered a starter.