The tanking/nontanking situation usually breaks down because people don't realize that overaggroing is not unusual if your tank is weakly geared or bad, but dying should still be rare. For example if I pull aggro on a Dullahan, and then it did an Iron Justice which I didn't avoid so I died. But the problem here isn't so much that I overaggro the Dallahan, but that I failed to dodge the Iron Justice. Sure, it'd be better if the tank held aggro but I am expected to be able to dodge an Iron Justice if I got caught in its radius. So lack of aggro is probably the tank's fault but dying is my fault. The correct outcome is that I have aggro but still survive by dodging the Iron Justice. Of course in reality usually either the DPS gets mad (for dying) or the tank gets mad (for losing aggro) and then things get ugly.
