I'd love a deep character customization. At the beginning you chose a height, weight, skin color, hairstyle, face, clothes and hair. And maybe in one of the cities there's a hair stylist or a clothing shop where you can buy hairstyles and clothes not available from the start of the game. Or you earn clothes throughout the game.
Like in HGSS, when you wear the track uniform during the pokeathelon or the Rocket uniform. I just think it'd be cool for everyone to look different during wifi battles and whatever other wifi modes they have planned.
Drug free. Alcohol free. Straightedge.