Since the Home Button is a moving part there has to be some degree of free play or looseness. But how much is subjective. Since the Home Button bothers you, this is a problem. I would make another Genius reservation, go to Apple Store a few minutes before your appointment, test some of the iPhone 5 display models. See if your iPhone 5 Home button is different. If yes, then when you see the Genius show them the problem and it will be handled right there under Warranty. Apple does not repair the iPhone 5, they will offer replacement iPhone 5 under Warranty. The Genius most likely will not open your iPhone for this problem, but if they do open it, the Warranty will still be fine and intact.