Cancellara's more of a pure TT guy than an overall contender, he's unlikely to be able to keep up with the leaders in the mountain stages. It's doubtful that he'd even be thinking about an overall win himself, he's more likely to target stage wins (particularly in the TTs).
Given the relative lack of mountains this year, I'm hoping for some all out attacks on those stages, rather than the marking tactics of last year, particularly as there's no guarantee of being able to claw back time in a TT between say, Wiggins and Evans.
The favourites being seemingly quite evenly matched gives this Tour the potential to be particularly intriguing (in theory, anyway).