Chesney's looked alright from what I've seen, not much more. He's only 20/21 like so we'll see how he develops over the next couple of years.
The point is though, it's risky to rely on him to be your no.1, because you just don't how he'll turn out. But Wenger will probably do this then buy a couple of wishy-washy attacking players who'll be great one game and fail to produce in the next 2, only for one of them to score a goal to give you a 1-1 draw at a relegation-threatened team to prove Arsenal's so-called mental toughness yet again.