I've never really thought of Cancellara as a GC contender. I think he's listed as more of a Super-Domestique for the Schlecks, and is more suited to smashing a time trial.
In my completely non-expert opinion I think Cadel's year was 2008, and he won't better his best so far. I would love nothing more than for Cadel to jump onto the top spot of the podium, but I just don't feel he has it in him. This won't stop me from barracking wildly for him, and therefore not being able to get to sleep after watching exciting summit finishes.