Didn't see a thread like this so I'm going to add it.
Sure the game play is an important part of a game but what I really like about a game is all of the unnecessary features that people add. Having the characters talk to each other would be a cool thing to see. Like when your away from the game and you have Ralph and Vanellope as playable characters they could say something like;
Vanellope: Hey Stinkbrain, you're smell scared away the player.
Ralph: *Sarcastically* Very funny fart feathers.
Or there could be something were Vanellope glitches on Ralph's shoulder and adorably chews on her licorice sweatshirt strings.
I always like Gimmicky things.