Wang has been "lucky" even when he was winning 19 games with the Yankees, that's just the way he pitches, he gives lots of ground balls and let his defense handle the rest.
He's also a veteran that been there long enough not to freak out in those situations and he has proved (so far) that he can handle being a starter.
Would i prefer him to just strike out or ground out 27 out of 27? Sure. But that's not who he is, he will sink the ball, give alot of singles, pitch deep into the game and keep your team in the game long enough that you can actually win it.