My idea in Clash Of Clans is adding light elixer:
Just imagine it could be stored in a prism storage it has a light elixer miner and it also has a light barrack.
It could also have simmilar troops to the dark barracks
Hog Rider Wolf Rider
Valkyrie Light Swordsman
Lava Hound DemiGod
Witch Arch Angel (Summons some kind of light minions)
NEW HERO: Wizard Prince