None of my real personal favourites went down (except for Ewan, and that was a rider's mistake); Alaphilippe and Carapaz were actually "winners" of the stage - but I found the stage design outragious, taking into account the size of the peloton and the positioning of the stage within the race.
Either you have a classic's stage with twisty roads - okay, but then you need some serious hills before the final or a big mountain stage before that. Or you have a full bunch sprint with many GC contenders still in it, then you need to design the final 30 km differently.
Yes, it's always rider's faults in the sense "if you had handled the situation perfectly you could have avoided it", but every route designer knows that not 180 people will handle every situation perfectly, so some minor mistakes or strong fights for positioning have to be taken into account.
Everyone who saw the final 15 km could see that something like this would happen before the race. Would be different if you could say "nobody could foresee this".
Reducing the peloton's size would also help and I would like it anyway.