Really, I think it comes down to which team can develop the best overall package during the off season. The total package isn't just the bike, but the rider, the mechanics, the management even the guy/girl who makes the coffee.
Now, over the last decade or so one Jeremy Burgess has been able to combine all these elements into a winning team, I see no reason why he won't do it again, and unless Rossi does something stupid and breaks himself I can't really see anyone beating him for the championship, which to be honest I find quite boring.