Like I said, my primary consideration is "what makes the tank/healer comfortable". If the tank wants to pull small (or I'm tanking and the healer would prefer I pull small), hey, that's what we do.
I will still generally offer regardless, because when they know the other half of the tank/healer pairing isn't going to be angry/mean if things go bad, folks are willing to give stuff a try. And sometimes it doesn't work out, and hey, that's the breaks. But sometimes it does, and I know few greater joys in leveling roulette than watching a learning tank as their confidence "clicks" and they realize "oh hey, I can handle this".
(I will also usually point out the caster, if there is one, that they can use LB to burn down a big pull like that a fair chunk. And I also enjoy watching the moment of realization as it becomes clear that, oh, hey, caster LB is really good at trash pulls.)
So, yeah, I agree it's not great play to force folks past a point where they're comfortable -- because, again this is a game. But I will absolutely offer to give it a go with them, and often they take up the offer, and sometimes that works out well. And the "holy heck, we just vaporized all of that at once" moments with folks who didn't think they could manage it -- and who then realize they can -- are sometimes the best part of roulettes.
