They already have the snow world, which is more than enough for me. Spooky worlds are also prevalent in Rare's games (DK64 even had 2!), but I'm pretty sure they already confirmed that one, too. The only thing I can think of that they're missing is a world that is based on water, like Clanker's Cavern, Jolly Roger's Lagoon, or Gloomy Galleon. I hope they bring some new ideas to the table, too, though.