he is also useful where Treasures fuel artifact sacrifice, improvise, or X-spells
Fight Rigging I have to say that Fight Rigging has to be the card with the greatest potential from the set, but for one reason or another, it has failed to be consistent enough to be in more than a tier 3 deck
That's what a subset of better-than-average players means in this case
Additionally, you might also want to focus on the fact that Arabella is an Artifact Creature and add some cards to take advantage of this such as Darksteel Forge (an expensive card at 9 mana, but a way to make all Artifacts indestructible) or cheaper pieces such as Voltaic Key which allow you to untap Artifacts for just 2 mana total
The only other potential commander, Arthur, Marigold Knight , plays into this last theme quite well
Cards like Mystical Archive: Mizzix's Mastery or Tibalt, Cosmic Impostor could provide more value and versatility in gameplay compared to the Double-Faced Substitute Card, making them better options for inclusion in a deck