I don't mind new people doing one of the listed hm's to get better gear. What drives me nuts, is are the people who Que for them without having done them in Story mode. I will put up with a new healer/dps/tank as long as they are willing to learn. I just did an Ess run, which is long enough, but one person decides to watch every damn cut scene, it gets to you. That should have been watched in SM, not with a bunch of exp people with you who would like to get it done. I used to laugh at people who kept spamming "spacebar", now, i feel thier pain. Watch the damn thing once, twice, 3 times, or howmany times you want... in STORY MODE. That is what its there for.
When i'm on my dps, i have no problem leaving groups that watch cut scenes, you will find another, and, I will find another group that wants to just get it done.
Getting stuck happens. As for pulling what you agro'd to group, well, in most cases, even after you die, they will find the rest of the group anyways.