I was looking through the skins last night trying to decide on one that I wanted to buy. As I was scrolling through them, I noticed only 3 battlecast skins (Xerath, Cho'Gath and Urgot). I also noticed only 3 Full Metal skins (Jayce, Rammus and Pantheon). I started to think about some champions that would fit these themes.

For the Battlecast skins, I figured that since they are missing a support, why not make Battlecast Taric. He could have full armor and his shield could be a solid chunk of steel or something. His shatter could be metallic spikes surrounding him and his radiance could have pulsing flames from his feet. His dazzle could fire a small missle that stuns the enemy and the heal animation could look like a red particle version of the heal. His hammer would be solid metal with metallic spikes that give off a red aura.

As for a top laner, I thought of Scion. His whole persona would fit with a battlecast themed skin. His axe could radiate the fire like aura when he activates it. His shield would have something similar to Urgot's in appearance. His gaze would be solid laser beams that hit the target.

When it came to the full metal skins, I thought of Kog Maw and Leona to fill the missing roles.