I would like to put some comments into perspective.
1) Nibali was the only gc contender to gain major time. The rest of the major GC contenders finished between 2-3 mins. What it shows is that Nibali was the only risk taker in the GC contenders.
2) Nibali had a great team with Westra and Fuglsang to help him
3) Kwiatkowski was the other GC contender to finish ~1 min as he is a natural rider of the cobbles.
4) Froome's problem was stage 4 crash and not stage 5. That is what made it extremely difficult for him and he crashed again. He was the only gc contender to DNF
5) Everybody knew the cobbles were coming. Punctures and crashes were expected.
6) Nobody could have predicted the rain 3 months back but everybody knew the rain was a certainty before the race. Without the rain, the GC would have been a lot more normal.
7) The reaction among the riders themselves is mixed. They always have the go slow or neutralization option. After all the riders make the race.
8) Many predicted a Froome-Contador showdown in the mountains for the Dauphine as well and look what happened. The top contenders have been taken out of the race due to crashes before
All in all the cobble stage causes a disturbance in the GC but does not decide the GC but can cause some of the contenders to get eliminated. However rain+cobbles = Carnage and Snow+cobbles = Devastation. So have it every year
