I agree Tank should pull as much as the tank capable of
but I also disagree DPS/Heal run ahead and pull without first trying to discuss with the tank for bigger pull
DF put 4 random strangers together and will probably wont see each other again in short time
show some basic respect to each other. Tank try to pull as much as you can, dps and heal try to talk with the tank first if the pull is too small/big