He's not a flair or flashy player.
British media love someone like that, a Gerrard or a Bale or a Suarez. Explosive players who contribute to the game in a very outward (For lack of a better term) way.
Ozil is a lot more subtle, he won't score a 30 yard screamer or volley it into the roof of the net, that is not his game and coincidentally it makes it more difficult for people to appreciate how truly good he is.
Look at how long it took for Scholes to be fully appreciated in this country, the fact that he was shunted out to the wing for the national team so lesser players could play in midfield was an absolute disgrace.
Ozil could dictate the play from midfield, put three chances on a plate for Giroud to miss and the press would still come out and say that he had a terrible game because he didn't score a goal or create an assist, ignoring his effect on our overall game.
He can improve of course, no denying that but he's second on the assist charts in the league so what does that say about all the players below him (including Silva, Mata, Hazard, Navas and Aguero)?