A new map based on a tropical island. There could be a huge docked cruise ship with plenty of loot and zombie's guarding it. A ship that can be a base for your community as well as Coast Guard stations filled with powerful weaponry...A rain system would be cool, the rain could come on suddenly out of nowhere and bring out of the rivers a new and powerful type of freak that is unique to the tropics but can only come out in the rain. New weapons like a harpoon gun or clubs with shark teeth for spikes would match the theme nicely.
I know an entire new setting would require all new assets and tons of work but I think it would add a vast amount of variety to this amazing game you guys have created, thank you for all of your hard work in making this game such a joy to play!