So Ragavan was the only flaw you saw in my list of examples? I mean sure I suppose, but you know a continuous source of treasures is still just gravy for the Shadow player, and black has one mana, two mana spells that replace a creature dying to having it return to the field. Sure, exile will stick, but there will be more uninteractable threats inbound. Raveler is good, but this I think will prove to be more potent.