I'm fine with the types we currently have... although a Light type would be nice. And merge Rock and Ground into a single type -- Earth.
Light would be strong against Dark (brightens the darkness) and Ghost (ghosts don't like the light), and weak to Earth and Grass (both can eclipse / dim the light).
Any sort of healing move would be reclassified as Light, along with light-based moves such as SolarBeam and Sunny Day. Some Psychic types (for example, Espeon) and some Normal types (Chansey) would become Light-type or part Light-type.
Also, Pokémon who live in the darkness (like Zubat) would be reclassified as Dark-type, or at least part Dark-type.
Earth-type would be immune to Electric and weak to Grass and Water (not sure about the other details... but like a combination of Rock and Ground)
Light would be strong against Dark (brightens the darkness) and Ghost (ghosts don't like the light), and weak to Earth and Grass (both can eclipse / dim the light).
Any sort of healing move would be reclassified as Light, along with light-based moves such as SolarBeam and Sunny Day. Some Psychic types (for example, Espeon) and some Normal types (Chansey) would become Light-type or part Light-type.
Also, Pokémon who live in the darkness (like Zubat) would be reclassified as Dark-type, or at least part Dark-type.
Earth-type would be immune to Electric and weak to Grass and Water (not sure about the other details... but like a combination of Rock and Ground)