Maps with unique terrain
Every map in the game is a flat, horizontal plane. Sure some maps have two stories, and a small hill, but I think it would be cool to see more verticality in maps. Building and gens perched on hills or maybe even mountains, pits, towers, ravines, etc.
Comments
Keep in mind, all maps have to be walled in. Having a map on a mountain side might be a problem. Also, certain killer powers have a really hard time with verticle differences. Doc for example wouldn't be able to shock ANYTHING if the whole map was slanted.