I think that Lewis will (of course) rack up some wins this year. But I think that Rosberg now sees himself as a legit WDC contender. He has the confidence now. As with any other sport or activity, a certain portion of it comes down to confidence. After Lewis had it wrapped up last year and let Rosberg up off the mat, so that he could celebrate his WDC and play with his celebrity pals, I thought, why waste an opportunity to crush Rosberg's spirit forever?! As much as Lewis has said that he's a fan of Ayrton Senna, some of the things that Lewis does make it seem that, while a fan, his personality and approach (commitment and focus) are VERY different. Based on how he played the game, I believe that Senna would have used the end of last season to establish complete dominance over Rosberg. There can only be one king on the throne.
So far, Rosberg has not fallen prey to the jibber-jabber mind games that Lewis likes to play in the press. He's just gotten on with it this season. And he's been fairly careful not to antagonize Lewis and create a spark. He's just gotten on with the program, while Lewis let himself fall off form last season and he's been hit with several issues this season. I'll still pull for Lewis, because I don't abandon my drivers in down times. But if Rosberg takes the WDC this year, I can say that a deserving driver won it.