User blog comment:Hadebrand The Bard/The Elder Scrolls VI: What?/@comment-1600847-20161128124930

As to the Black Marsh being entirely one climate/vegetation (swampland) and therefore unappealing, the same was said for Skyrim before the game came out. The province in lore was a snowy wasteland, but Bethesda changed it to include forests, plains, mountains, hotsprings, etc. They could do the same for Black Marsh.

For example, they could limit the swamps to the centre and west and put jungles/forests to the south and east, mountains and rocky valleys to the north along the Morrowind border.