The mage needs to wait to enter the fight until things are fully underway. You want to avoid getting viper stung or drained early due to terrible mage mana efficiency. So once chaos is ensuing I go ahead and get into the fight. I'll sheep the lock and try to get a shatter on the hunter, CS the druid, and then sheep so that our druid can come get a cyclone off on him. We'll go several cyclones into a bash and by that time the hunter should be dead.

The important thing to consider is that a druid can avoid getting burned pretty easily, and a warlock/hunter is not going to gib the warrior if hes sticking the hunter. If things go poorly, LOS as much as possible.