I disagree only because there are people like me whom HATE not knowing how a dungeon works. I'm fine redo'ing a dungeon if need be (especially one I know I will be re-runing again and again at some point). What I can't stand is not knowing what I have to do.
So I usually tell the new players right off the bat, if you wanna know how the dungeon is progressed, skip cutscenes to keep up with the group and I'll slow the speed down a bit (as i am usually MT during). But I always tell them if they wish to watch the cut-scenes, then feel free to do so, but unfortunately, it will be at the expense of them doing anything in the dungeon/knowing what to do.
I wouldn't halt an entire group by an extra 30 min for a single new player (or even 2).