I just look at it as there are 3 steps to understanding a dungeon (this really only applies to Mainline anyway, and there's only two of them).
The other dungeons the CS's are so short it doesn't matter.
Steps:
1)Watch the CS for the story
2)Do the dungeon to figure out how to do it
3)Farm
This isn't directed at YOU. This is directed at veterans to let people enjoy the game. If you want to skip so you can cut down on step 2 and then watch the CS later. Go ahead.
But don't make other people do what you want them to do when you don't even need them anyway. I'll bet you can run Mainline with 4 even level synced.
I'm saying this just to let new players be comfortable and not get stressed out. At least give them the option and don't be a dick about it.