While I can't wait to someday get a flip planeswalker of him in similar fashion to Nicol Bolas, the RavagerNicol Bolas, the Ravager, I still think that for now we should do the non-obvious thing and allow the most legendary Spirit Dragon to compete, despite technically not being a Dragon or a Spirit
Armarouge can move your Fire Energy from your Benched Pokmon to your Active Pokmon, allowing for Trinity Novas Energy attachments to fuel dangerous attackers like Armarouge ex (ex), Delphox V (V), Rayquaza VMAX (VMAX), and Radiant Heatran ()
A lot of things in cube are cheap and there are plenty of duals without basic land types
Artifacts your opponents control enter tapped
If they're normally instants or sorceries, they won't be counted