I have had no issues with tanks pulling large groups. Never let one die; though one did dip low a few times because he had no gear or understanding of cooldowns. I never gave that tank shit though because good healers can carry bad tanks in dungeons.

Although I have seen my fill of terrible healers. Every PUG cohealer I've had has been horrible and useless. I guess they got use to not having to think in HW content(put HoT on tank and AFK). Now there's a small amount of thought that needs to go into some content. Not much, but some. However I believe they will adapt.