Agreed on above post. I play both tank and healer. I also have SAM at 70 so I know a little about dps too. To add a little more, kill rate is also important here. Even if the tank is capable of withstanding multiple mobs and the healer is comfortable with that pull, if the dps speed is slow (this can be anything. Team composition, split target dps, lack of gear. You just don't know what you encounter on pugs) the fight will slowly turn south (this can lead to anything too. Tank will run out of cooldowns, healer's mana issue etc). Pulling more in stormblood dungeons also means you can simply cut off the healer's dps by a large margin. Yes I can holy two or three times to stun lock them but I will soon have to follow by healing if the dps is low, or tank is not using cooldowns.

I stated on another thread but for me, mass pulling needs a lot of conditions met (which is completely unknown on pugs) and even if you can pull them off the outcome is minimal. At least from my experience in the Stormblood dungeons. (old content dungeons usually has less issues due to the players being overgearing the content by a large margin).