Until Evans can show that he has what it takes to hang with the serious climbers on the toughest climbs in the world he is not going to win a grand tour. He's great on short climbs, he's great on long steady climbs that aren't too steep, but in every GT he has contended in so far he has failed to stick with the likes of Contador, Schleck and Basso on the long super-steep climbs.
That said, this year could be his best chance of winning Le Tour since 2008, and given his age and the possible return of Alberto next year it may well be his last. If Andy Schleck has a disastrous time trial, as he does every now and then, Cadel could be in with a real chance. He's going to need some luck, though, and either mistakes, inconsistency or bad form from Basso, Gesink, Sanchez, and the other guys who can out-climb him.