I'm gonna say something unpopular: I don't like to rush.

[ItMe]

Tanking is the same whether you pull 1 pack or 3 packs. Tank stance on, AOE, use cooldown. Besides, tanks don't start level 80, you should have enough practice by that point.

No way man. There's a big difference in how you use your cooldowns depending on if you're saving them for the next pack, or chugging through them all cuz the miniboss is next and those are always easier to tank than mobs.
And you're right, tanks don't start at 80. But I've read more than enough posts on this forum about people grumbling about slow pulls in low level duties to know that doesn't really make a difference. When I was learning I was expected to PERFORM in ARR content and people would literally scold and mock me if I used grit.

No, I'm trying to say the bar is so low you don't need to be a tank master to achieve a large pull, so double pulling also is not an issue. If you are learning to tank, the best thing to do is to push your boundaries and not wallow in your comfort zone. The worst that can happen is you die, which is not a big deal, and you'll have learned something, pulling one pack because you're learning (especially if you're level 50+) is absolutely a detrimental attitude for yourself

Is there really no conceivable situation where someone might still pull less?
Perhaps they just ran this duty, and KNOW they can't manage more mobs, but still haven't levelled past it and are running it again.
Perhaps they see the healer is undergeared and pull slower. I know I've been there and still had a DPS still gets unhappy about the pace.
Perhaps they fucked up and actually need to slow down. Maybe they hit too many cooldowns before or hit one on accident and don't have the stuff to take another big pull.
Perhaps some people just don't learn by that trial by fire method and they want to ease into things with a more measured approach.
Yes, learning and pushing yourself are important, but that doesn't mean you're only option is big pulls.