We should totally have a jungle area next to the marsh areas, but it'd be so dark there you'd only see silhouettes of creepy plants and tribal stuff, with lots of flamey torches! I thought of this after seeing Naraka because I absolutely love that area and want somewhere similar so I can have a house there <3
Underwater areas too! We could use fish as moving platforms to get to high places and could have Net Trees that you harvest to get salmon :33
Also whoever designed the Uralia area is amazing, we need a bigger island like this! Possibly with a huge mountain full of caves and secret passages. Then at the top of the mountain we could have a Sky region where you jump across clouds and air jets, and there's a ton of gas plants!
Some new wildlife would be great too :3 We could have kitties that follow you around and give you syrup when harvested.