I don't get all this Light and Dark being mutually SE bullshit. Darkness is simply the ABSENSE of light, if you're going to ignore the fact that the "Dark" type is actually the "Evil" type. There is no physical manifestation of darkness (unless you have negative photon generation, which could be incorporated into an ability, perhaps), only the physical manifestation of light, which can be absent from a battlefield.
Light:
SE to:
Dark, Ghost, Fighting, Bug, Dragon (Bug is the weakest link, remove it if anything)
Weak against:
Electric, Fire, Grass, Ice
Deals no damage to: Steel
Recieves Double Damage from:
Poison, Ground, Psychic, Normal
Resists:
Fighting, Fire, Electric, Dragon
Takes no damage from:
Dark
I see no flavor reason why this couldn't work. Might serve to nerf some dragons, but it wouldn't do jack shit to Steel types.
