For Goblin boss, you can provoke the landslide tank buster after 4 stacks of debuff when he becomes a giant. You don't even need to Tank Swap since after the landslide he won't cast another until provoke cooldown is up again from what I've seen. So let MT get stunned from 4 stacks, get OT to provoke the boss, use defensive cooldowns if they want to (They don't have to since they don't have any def down debuffs) and the MT can pick up the boss again when they get control back.