If there's gonna be at least one new type, it should be Light. Trumps Ghost and Dark, halves on Psychic, Grass, and Steel, and weak to Dark and Fighting. (this means no more "Jesus Christ" Pogeys like Sableye and Spiritomb)
Poison needs to trump Bug again, and it should also trump Water. (because lately, this type is getting shafted)
Introduce more Electric and Fire types. (they too are shafted, at least in numbers)
Make Kirlia only evolve to Gardevoir if it's female.
Make Mime Jr. and Mr. Mime 100% male.
And I think thats about it for me; just some battle changes.