You're putting words into my mouth.
Hamilton was expected to walk all over Button, like Alonso has done to Massa. Button has showed him up in that respect because all of a sudden everybody who was supporting Hamilton and bashing the Button 'victory' supporters from 2009, were proven to be wrong in their assumption that Hamilton is the best driver. I never said Button dominated Hamilton; My point was that Hamilton didn't. They have been relatively evenly matched whilst they have been at Mclaren. Sure, Hamilton had a bit of bad luck in 2011, but Button has had his fair share of bad luck here and there (See Spa 2010 for example).
Button is very vocal when the car balance isn't good, and this affects his performance. His bad races stand out in results because they are non-points finishes, but he makes up for this with his consistency when the car is working for him. When Hamilton had a bad weekend, he just crashes (Spa 2011) or loses lots of places from his qualifying position (Bahrain 2012). Not to mention how every on of his wins for Mclaren since 2010 have been from the front row of the grid, whereas only 3 and of 7 of Button's has.
Now Lewis is moving to Mercedes, people and certain news sites (Such as the BBC) are claiming he will have 'unequivocal' number one status when they most likely have no idea of the terms in the contract Hamilton has with the team. Nico Rosberg matching Michael Schumacher obviously means Hamilton will walk all over him.
I say again, people should not underestimate Hamilton now that he's driving a Mercedes. But lest people forget how dominant Nico was in China. If they have a fast car, Nico will be right up there with Hamilton. Lewis will by no means be the number one, it will be very similar to his time at Mclaren; He'll be faster but he's not Alonso, he's not going to dominate.