Pokémon X and Pokémon Y

We already have a "good" type in the form of Fighting, which represents Justice and Honor, making it a direct counter to Dark.

Not opposed to a light type in the slightest. But I'd like to see it actually be based off light instead of "light is the good type!"

Indeed. And instead of using Malthe's idea with Light and Dark, do it with Light and Ghost. (Of course the common theory involving new types is also adding Sound type, so how would that factor in?)