first week, people will be confused, frustrated, some will leave, others will stick it through, thinking they can handle it. They'll handle it the first 2-3 times, and after that, will swear off this dungeon set ever again.
after first week, and during 2nd week, you'll see people asking for runs through the specific dungeons so they can get through them at all.
After 2nd week, SE will have the numbers in, and probably make a decision on either keeping things as they are, or changing them back.
You can say various things about Yoshi P, but he's not a braindead corperate minion.
Nor is he a blizz employee who thinks he knows what's best for the players. If something's wrong, he fixes it. I fully expect him TO fix this, it'll just depend upon the time frame.
My guess is, what'll end up happening is they'll make it so the entire group has to choose to skip the cutscenes before they can move on. Which can be a problem with slow clickers. Like myself.