I think Jenson learned the hard way that in order to extract the best from himself, he needed to extract the best from those working around him - to this end he has built upon the success and status he attained with Brawn to galvanise the McLaren team around him.
It seems clear that he got all the "playboy" stuff out of his system while at Benetton, at the same time learning the painful lesson that driving ability alone will not make a dog of a car suddenly start to purr. I think anybody who had watched him claw his way up the grid from 2002 to be chasing the Ferraris in 2004, were perfectly able to see there was a very good racer there - the frankly rather silly kerfuffle over his contract negotiations during this time may have coloured many people's opinion of him however, and the impotent Honda Earth Cars of 2007 & 2008, along with the arrival of a certain young Englishman, further masked his potential from general view, and in many respects he got written off as a "never likely to be" man.
I think this overall view of him still managed to stick, even throughout his title-winning campaign, leading to an awful lot of frankly ludicrous "he didn't deserve it" and "my granny could've won in that car" comments (which still make me furious, as nobody wins a WDC without a good car and a lot of determination and ability).
I, for one, am not in the least bit surprised that Jenson has slotted in perfectly at McLaren - he has a fearsome personal motivation and work ethic (triathlons for fun??), and for those of us not bedazzled by Lewis' explosion into F1, a clear and steely ability as a racing driver.
Don't get me wrong: even as a Button fan, I still think Lewis is probably the most talented F1 pilot there has ever been. I think all he really lacks is the experience and sense of perspective that a tougher climb up the grid may have given him - it is easy to forget that he suddenly had everything he ever wanted at a very young age (millions in the bank, a dream job, celebrity girlfriend, WDC in his second year, feted as the second coming of Ayrton, slayer of Alonso, etc...), and who could blame him for wanting to explore some of the perks that being a stupendously-talented racing driver bring?
All the conspiracy theorists who blame McLaren or Whitmarsh for sabotaging Lewis' prospects, or favouring Jenson over him, are missing the point completely - the only thing affecting Lewis' chances is Lewis himself. If he parked the perks and spent more time applying the lessons of Vettel, Schumacher, Alonso & Button and built his team around him, then he would be utterly unstoppable.
Perhaps it is a good thing for the rest of the grid that he hasn't grasped this (yet) - but when he eventually does, beware of the backlash!