Just looked at stone guard.
I don't get how his damage is that low though. Even with him not using all the thing mentioned in other posts.
I'm not tanking just one dog, but i did good 90k on them tonight, and i my ilvl is 8 below his(on item being dps though). Doing 16k is really low even without any vengeance at all.
If his spiking is too scary, let him get some stam i guess. I went a bit high on it myself, but it makes healers able to relax a bit when the spike isn't half my health but just 1/3rd.
Overall he would probably do a fair amount more damage just binding RS/HS/DS and jamming all 3 of them all the time, to avoid not using ready runes/Runic power(not really advicing that :P )
Noticed he's having very little overhealing. Maybe he's just idling Death strike while waiting for damage to come in, to heal more <.<
You don't understand the mechanics of that fight. When there is only one dog, it gets a damage reduction buff. That explains most of the low damage done.