Why not an elemental reaction system instead of a wheel? If anyone remembers fighting Soulcage in ffix if you cast fire on him he would catch alight and his attacks etc would change. SE could in that case have differing effects across different enemies when casting elements on them. Maybe even have element reaction combos. So while you might have a best element for a particular enemy/boss it wouldn't carry over to every enemy so there wouldn't be a best for all enemies. Elemental reactions could help or hinder the team depending on the effects and the party makeup.