I honestly don’t dare to make a prediction.
Ferrari seem to have found some pace they lost after the beginning of the season, while Mercedes is sure to claw back after 2 bad weekends. Meanwhile, Lotus, despite their bad qualifying, had good race pace at Monza, but appear to be falling behind in the development race. That might be less influential if Ferrari and Mercedes decide to focus on their 2014 cars, though.
Alonso and Hamilton will surely keep on scoring podiums and perhaps wins. Massa has been on and off all season, but usually doesn’t make the podium even on his on-days, while Rosberg has won races. He seems to be a little off since his win at Silverstone, though and I’m not sure he’ll bounce back. If he does, Mercedes probably have the strongest pairing and should edge Ferrari, provided Massa doesn’t maintain his Monza-form. Raikkonen and Grosjean need to put in some excellent qualifyings and races if they want to keep up with Ferrari and Mercedes, but Grosjean has been more off than on this season and has some terrible luck.
I’d put a very small amount of money on Ferrari, mainly because I expect Alonso to score the most points out of the 6 people driving for these teams. If Rosberg finds his earlier form, though, it’ll be hard for Ferrari to maintain 2nd even if Massa retains his Monza form. Lotus seem to be falling behind, though.