Using the ESPN Power Rankings as reference, which only considers (the equivalent of) palmares to the extent that they inform the present (for example, Froome's 2016 Tour is relevant, whereas Contador's 2007 Tour is not). My ranking essentially answers, "You line everyone up this year, where do they fall in order of most likely to win to least?"
1. Froome - will remain number 1 until defeated in his year's primary target GT
2. Dumoulin - better TTer than Froome; didn't fare too poorly on the climbing against Quintana, Nibali, and Pinot; obviously people will have a problem with this one, but you can't put Quintana above Dumoulin when Dumoulin just beat him despite losing 2 minutes for a dump
3. Quintana - very consistent; hard to imagine anyone but Froome and Dumoulin beating him if he is close to his A game
4. Valverde - dominant spring; past performance in GTs indicate he might be overranked, but this was his best spring ever
5. Porte - should have gotten second last year in the Tour; obviously has significantly poorer palmares than two below him, but higher power ranking in the present
6. Contador - performance in weeklong stage races, similar to Porte, give the power
7. Nibali - beat Contador last time they raced the Tour, though Contador had raced the Giro, 3rd in the Giro this year, 1st last year
8. Pinot - very close to Dumoulin, Quintana, and Nibali in the Giro
9. Chaves
10. Bardet