http://www.reddit.com/r/smashbros/comments/1vwn8f/bill_murray_confirmed/
One theory I heard was that customization could be like stickers giving buffs and stuff but only in the 3DS version.Also to a point of character customization HATS and COLOR SCHEME CHANGES AND CIRTAIN PARTS FOR CIRTAIN CHARACTERS which brings up a diffrent point I just thought of by playing the "story or adventure mode" you unlock features for characters that grant abilities and remove abilites that can help in some situations and diffren mode and stuff