Any ally with 1 Defense is a huge liability for Graccus, as he starts taking hits like a clothie would. My favorite part of the Goblin Fog vs BIG matchup is to rip through an Irana with Graccus support with my Shredder and just send 4 damage to Graccus on a crit, maybe more if he flubs his own defense on the crit area attack.
Against Vashj it's just BAD. You just shoot Irana with melee until Graccus is close enough to the 2 health threshold that it dies from one magic attack, and you can plausibly kill both in one tick.
As for Bolvar's Retribution, it suffers from the problem that it basically meshes badly with Bolvar's own main attack.
If anything, Savin Wall + Irana/Bolvar would probably be a better idea.
"The beatings will continue until morale has improved."
- Standard corporate management technique