I think Lewis will win another WC. But he needs to get his head together first and get a car close enough to the sharp end to let him do it.
Of course he will win another championship (providing he stays healthy), that's a given. However, he doesnt want to finish his career as a double World Champ. I believe he is aiming to become an all time great (ie. to be as decorated as MSc).
The problem for Hamilton is that when he burst on to the scene, he didn't expect to have to deal with a guy called Vettel.
Another point of note was that last year, most of us were saying that if Hamilton can get a car which is "almost" as good as the RBR, he could compete against Vettel for the title. Well, based on this year's performances, this won't be happening.
Hamilton now needs a car which is at least as good as Vettel and this is why I am saying that Hamilton has to get himself in an RBR, alongside Vettel, to put Vettel under pressure and attempt to break him mentally. Hoping that McLaren will come good is all very well, but Vettel is racking up race wins, pole positions and WDCs, while Hamilton is waiting, hoping and getting older. His best years are being wasted.
I saw the interview today with Massa and I have to say that I am beginning to agree with him in that the FIA have to look at his driving. The guy is crashing in to someone, in almost every race.
Button on the hand is avoiding all the crashes (with the exception of Canada) and is getting good points finishes. On top of this, for half of the season, he has definitely driven better than Lewis "car crash" Hamilton. The worrying thing for Hamilton is that, his poor (car crash) form doesn't seem to have ended yet.