Some dude (from GAF I think) joined my Inferno Act I run yesterday (the one I faceroll mostly, even with some Mf pieces on) and it became impossible. Sure, I was not traited for taunts/heals/escapes, but the fucking spike in difficulty was stupid so he pretty much left 5 minutes later, lol.
I guess the problem with melee classes is that you become the default tank like this was a Wow raid (or at least glass canons expect you to be), and of course your DPS goes to shit if you try and fulfill the role properly. Whatever happened to the "every class is a DPS class" they were going on about before release? Pretty hard thing to do when your stats hunt becomes Resistances > Vitality > Armor > Str