I'd go Zabaleta, Debuchy, Coleman on talent/capability - but reverse it for performances this season.
I used to rate Sagna, and he is reasonably solid defensively, but I think he's deteriorated massively recently and is often Arsenal's stand-out weak link at higher levels, IMO. He's got a bit of the Gutierrez about him in that if he is facing his own goal and shielding or retrieving the ball, if you come within 5 metres of him, it's an Arsenal freekick, because he 100% will be on the ground. He's great at winning them off refs.