I'm very happy to see huge majority of players commenting and liking the posts in this thread understand that when people are running the dungeon for the first time for the story, the group should let them experience it without rush and skipping the story part of it.

In my LS, I've tried to organize LS groups for all members who are up to CM and Prae so no one is ruining the experience for them. That's where they can also experience their first times doing 8 member content which is great experience for especially tanks and healers, I think. We usually don't even explain any strategies for the fights but let them figure out stuff themselves. It's sad when people forget they were once new and feel like their time is so very precious they can't let new people experiment and experience things.