Thibaut Pinot was just a 'baby' when he started his first Tour (1911/12 I think?) but he did show great potential. He has obviously gained experience but I have not any cycling this year yet.
Contador is ALWAYS dangerous (I think)
Three different mountains to tackle too, In between the Pyrenees and the Alps, they are going to have a couple or so climbing days in the Massif Central - which is not always as innocent as one thinks, perhaps not as tricky as the other two, but still.
All in all, I think the accent has been put on mountain days and that will take its toll on the riders, especially if hot!