You could probably have no mountains and the result would be the same. It's a 3,000km death march and the GC winner will always be the guy with the best funded team. The best funded team will always be able to pay $$$ for the best riders. The best riders are the ones who are genetically blessed to recover quickly and be strong but efficient.
You act like Geraint is some twig but the guy has Olympic gold from the team pursuit so plenty of power.
Sagan's awesome, but I wonder why he gets none of the hate? He's dominated the green jersey, except when he was DQ'd in '17.
I think what would make a wild tour is if the GC winner couldn't compete with the same team the following year or two.