Darkest Dungeon is the PERFECT platform for churning out more DLC that is still gonna be enjoyable 10 years from now.
>gameplay is pretty much established
>game world allows for easy exploration of more themes set in the same world
JUNGLE WORLD
>the Ancestor's jungle expedition: coastlines where the explorers landed, deep jungles, maya temples, caves
>Diablo II act 2 style jungle monsters with blowguns, torches and tiki shit, jungle fanatatics, huge mosquitoes, other explorers gone mad, tigers, gorillas etc
>torches would be useful again
>base is a small jungle village with jungle people, new heroes arrive by boat
>can be attacked by vietcong style rebels
>IT AINT ME starts playing
DESERT WORLD
>Ancestor's desert expedition: Morocco style desert cities, wide sand dunes, deserts (day/night), oases, sand-monster underground saves, spooky pyramids
>huge scarab monsters, snakes, sand-dwellers, dervish style creatures, British safari style colonialists gone mad
>possible dehydration mechanic
NORTHERN WORLD
>Ancestor's north pole/fjord expedition: frozen shores, fjords, tundras, snowy mountains, frozen caves, dark winter forests
>frozen skellingtons, bears, frost/stone elementals, 1% chance to have bigfoot spawn, yetis, other furry monsters
>base is an alaskan settlers trapper style outpost village that you have to set up, with log cabins, mules and other shit
>possible freezing mechanic, torches also provide warmth
ASIAN THEME
>Ancestor's far east expedition: chinese cities, bamboo swamps/jungles, the great wall (literally made for a DD-level), imperial palaces with giant golden lions and dragons etc, rice fields with tiny villages in them
>imperial chinese style soldiers, suicide bombers with colorful fireworks and shit, giant ornamental cannons, tigers, samurai-style enemies, weird floaty chinese dragons, combat staff wielding apes, cranes or whatever
>base is as old temple site the ancestor wants to explore further as you progress through the missions