ILKCMP's avatar
I don't really think we need any new types at all, but I'm not sure we agree on Light-type. Dark-type, as a whole, is more heavily themed on fighting dirty and using underhanded tricks on your opponent. Fighting-types are, in that regard, the foil to Dark-types (fighting fair). To an extent, Fairy-types are as well. I think the introduction of the Fairy-type was partly Gamefreak's answer to "Light-type," seeing as many Pokémon fans wanted a Light-type for were included (such as the Togekiss line). From a standpoint of physical light, that can be covered by existing types, as light-based attacks are a variety of types.

While I agree that sound-based Pokémon are best suited for other types, mostly Normal, I think it would have the best chance to become a type in the future. That being said, I don't think it'll happen.