Aside from lacking a way to draw cards on his own, hes basically the whole package
A tutor like From Father to Son that can search for a vehicle
Shantottos Coercion Diabolic Intent is probably playable with a bunch of Hecteyes, job select stuff, and exciting cards to tutor
Suddenly Evolving Wilds is a better Prismatic Vista, and Path of Ancestry is a better Command Tower
Steel cards often pair well with some of the best item cards in Lorcana, which can help bring their cost down and boost their power further, and action cards that can provide a faster response to your opponents moves
10 Arthur: Wizard's Apprentice 207/204, Amethyst The Sword in the Stone has an impressive showing in Disney Lorcana: Rise of the Floodborn , with Merlin receiving a number of cards based on various transformations from the film