Our method is to tank shannox and riplimp *very* far apart (one healer that can heal one of the tanks is not in range for the other). Our prot warrior on riplimp, when seeing the spear throw, heroic leaps and intervines twards me. The dog follows him untill in melee range before going back for the spear. In this moment he is running back he is vulnerable to slows. Our mage slows the dog. By the time he gets to the spear, and back to shannox both my stacks and the warriors reset. I didint move at all.
Naturally, you dont have a prot warrior or a mage in your composition, but you can work around and keep a similar strat. Have the priest lifegrip your bear and them have him charge to shannox when spear is thrown. Have the lock or S priest slow him.
The idea is to have the riplimp tank get his dog as far away from the spear as possible before the dog turns to get it, enhancing slow time on the dog. If you dont have that slow time this fight is chaos. Melee dps cant dps at all if you keep kiting the dog and their complaint is valid, your not preforming the fight as intended.