Surprised nobody suggested this yet (At least not with the word "Random" in the topic title), but I'd love if we could customize the random survivor select option. I've even seen a few people in-game ask for the feature to be implemented, too.
I'd personally love to click random and be given Wes, Warly, or Wormwood at random, while other players might want to do something like pick everyone except Wes (The heathens). By default random could stay true random so anyone who prefers the current functionality can maintain it (or customized random is added as a new slot), but I think this change would really make the random button a lot more useful for a lot more players.