I prefer the idea of Normal resisting Fairy. It gets a resistance to cancel out it's fighting weakness, so it's a perfectly balanced type in terms of resistances (1 immunity, 1 strength, 1 weakness) I don't think it needs an offensive buff.
Personally I agree with what other posters have been saying. Seeing a move like Tackle do super effective damage would be broken. A resistance (or immunity) against Fairy would be better, if it did in fact receive a boost.
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