Sector
Sectors would allow the map to consume less memory that the voxel mode, and allow for more complex maps, and would allow improved npc ai, akin to Duke3D scripting. Npc's etc could still use the regular FF4 imposter graphics, along with textures being from the FF4 tile set. Would allow more advanced door animations, floor region shifting, more accurately sloped floors, more accurate stair wells etc, advanced duplication of various sectors using a prefabricated sector library.