Ravager comes out for 2 mana.
Ravager gets out from under Arrest, Dark Banishing, or any other removal by saccing himself.
Ravager loves your modular creatures. LOVES them. Likes to eat them with a side of fava beans.
Ravager eats any of your artifact guys that's about to die.
Overseer is, what, 6 mana? End of story. Casual-only.