He cripples us up front with his awful touch. He's no better than Giroud there, and we lose both the linkup play and the physical presence.
There was a telling moment in the FA Cup final where Mertesacker blasted a 60 yard ball up the field. Özil took it down on volley and passed it gently to Theo with a single touch. It was a world class skill. Theo didn't want to meet the volley pass though so he waited for the ball to bounce instead and fucked everything up. I'm sure Özil cried on the inside.
Earlier in the same game Özil had played a great throughball into the path of a running Theo. Walcott tried to bring it into the field but his touch was so heavy that it ended up looking more like a shot aimed towards the corner flag. He did the same thing again in the second half, and was offside to boot that time.
Mirth is right; Theo needs to start on the wing where he gets a fullback to skin instead of two centrebacks.