for everyone that voted poorly, can you explain why?
If the goal is to make as flat a world as possible,
sacrificing all to reach that goal...
Something like this is flatter, overall.
[WORLD_GEN]
[TITLE:FLATWORLD]
[DIM:65:65]
[EMBARK_POINTS:2500]
[END_YEAR:300]
[BEAST_END_YEAR:300:99]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:0]
[ELEVATION:100:350:0:0]
[RAINFALL:0:0:100:100]
[TEMPERATURE:50:75:0:0]
[DRAINAGE:0:100:100:100]
[VOLCANISM:0:0:0:0]
[SAVAGERY:0:100:100:100]
[ELEVATION_FREQUENCY:4:9:0:0:0:1]
[RAIN_FREQUENCY:1:1:1:1:1:1]
[DRAINAGE_FREQUENCY:1:1:1:1:1:1]
[TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
[SAVAGERY_FREQUENCY:1:1:1:1:1:1]
[VOLCANISM_FREQUENCY:1:1:1:1:1:1]
[MINERAL_SCARCITY:2500]
[MEGABEAST_CAP:4]
[SEMIMEGABEAST_CAP:9]
[TITAN_NUMBER:3]
[TITAN_ATTACK_TRIGGER:0:0:100000]
[DEMON_NUMBER:22]
[NIGHT_TROLL_NUMBER:11]
[BOGEYMAN_NUMBER:0]
[VAMPIRE_NUMBER:11]
[WEREBEAST_NUMBER:11]
[SECRET_NUMBER:22]
[REGIONAL_INTERACTION_NUMBER:0]
[DISTURBANCE_INTERACTION_NUMBER:0]
[EVIL_CLOUD_NUMBER:0]
[EVIL_RAIN_NUMBER:0]
[GOOD_SQ_COUNTS:0:0:0]
[EVIL_SQ_COUNTS:0:0:0]
[PEAK_NUMBER_MIN:0]
[PARTIAL_OCEAN_EDGE_MIN:0]
[COMPLETE_OCEAN_EDGE_MIN:0]
[VOLCANO_MIN:0]
[REGION_COUNTS:SWAMP:0:0:0]
[REGION_COUNTS:DESERT:0:0:0]
[REGION_COUNTS:FOREST:0:0:0]
[REGION_COUNTS:MOUNTAINS:0:0:0]
[REGION_COUNTS:OCEAN:0:0:0]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:0:0:0]
[REGION_COUNTS:HILLS:0:0:0]
[EROSION_CYCLE_COUNT:0]
[RIVER_MINS:0:0]
[PERIODICALLY_ERODE_EXTREMES:0]
[OROGRAPHIC_PRECIPITATION:0]
[SUBREGION_MAX:2750]
[CAVERN_LAYER_COUNT:3]
[CAVERN_LAYER_OPENNESS_MIN:1]
[CAVERN_LAYER_OPENNESS_MAX:2]
[CAVERN_LAYER_PASSAGE_DENSITY_MIN:0]
[CAVERN_LAYER_PASSAGE_DENSITY_MAX:0]
[CAVERN_LAYER_WATER_MIN:25]
[CAVERN_LAYER_WATER_MAX:25]
[HAVE_BOTTOM_LAYER_1:1]
[HAVE_BOTTOM_LAYER_2:1]
[LEVELS_ABOVE_GROUND:5]
[LEVELS_ABOVE_LAYER_1:20]
[LEVELS_ABOVE_LAYER_2:2]
[LEVELS_ABOVE_LAYER_3:2]
[LEVELS_ABOVE_LAYER_4:2]
[LEVELS_ABOVE_LAYER_5:3]
[LEVELS_AT_BOTTOM:2]
[CAVE_MIN_SIZE:1]
[CAVE_MAX_SIZE:1]
[MOUNTAIN_CAVE_MIN:0]
[NON_MOUNTAIN_CAVE_MIN:0]
[ALL_CAVES_VISIBLE:0]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:2]
[TOTAL_CIV_POPULATION:1]
[SITE_CAP:1]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:0:0:0]
[RAIN_RANGES:0:0:0]
[DRAINAGE_RANGES:0:0:0]
[SAVAGERY_RANGES:0:0:0]
[VOLCANISM_RANGES:0:0:0]
Away from mountains or lakes, worlds made with this worldgen are either 0 or 1 elevation in every region. Many many many regions are nothing but zeros.