My understanding is that changing the raws in any way will change world gen. Remember, you're influencing the history of the world by making your giant ravens disappear! Can you remove the raws from your save, instead of the main game?
I get the exact same site as far as minerals, ores, and soil layers--that's all identical. It's just not generating with the magma pool.
I could, but I'm iffy as to how editing the raws would work... the annoying animals would still exist in the game files; seems to me like that's begging for bugs/crashes.
How do the world-gen pros get a decent mix of good and evil landscapes?
I'm by no means a pro, but:
[WORLD_GEN]
[TITLE:NEW RANDOM SEED]
[DIM:65:65]
[EMBARK_POINTS:1274]
[END_YEAR:1050]
[BEAST_END_YEAR:1000:20]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:1]
[ELEVATION:1:400:400:400]
[RAINFALL:20:100:300:300]
[TEMPERATURE:35:70:300:300]
[DRAINAGE:0:100:300:300]
[VOLCANISM:35:100:3200:3200]
[SAVAGERY:35:100:400:400]
[ELEVATION_FREQUENCY:2:1:1:1:1:1]
[RAIN_FREQUENCY:2:1:2:3:2:1]
[DRAINAGE_FREQUENCY:2:1:1:3:2:1]
[TEMPERATURE_FREQUENCY:2:1:1:3:2:1]
[SAVAGERY_FREQUENCY:2:1:1:4:3:2]
[VOLCANISM_FREQUENCY:2:1:6:8:6:3]
[MINERAL_SCARCITY:800]
[MEGABEAST_CAP:8]
[SEMIMEGABEAST_CAP:18]
[TITAN_NUMBER:12]
[TITAN_ATTACK_TRIGGER:80:500000:1000000]
[DEMON_NUMBER:18]
[NIGHT_TROLL_NUMBER:4]
[BOGEYMAN_NUMBER:4]
[VAMPIRE_NUMBER:24]
[WEREBEAST_NUMBER:24]
[SECRET_NUMBER:24]
[REGIONAL_INTERACTION_NUMBER:24]
[DISTURBANCE_INTERACTION_NUMBER:24]
[EVIL_CLOUD_NUMBER:12]
[EVIL_RAIN_NUMBER:12]
[GOOD_SQ_COUNTS:450:500:1000]
[EVIL_SQ_COUNTS:450:500:0]
[PEAK_NUMBER_MIN:3]
[PARTIAL_OCEAN_EDGE_MIN:2]
[COMPLETE_OCEAN_EDGE_MIN:0]
[VOLCANO_MIN:5]
[REGION_COUNTS:SWAMP:80:0:0]
[REGION_COUNTS:DESERT:0:0:0]
[REGION_COUNTS:FOREST:325:0:0]
[REGION_COUNTS:MOUNTAINS:300:0:0]
[REGION_COUNTS:OCEAN:300:0:0]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:300:0:0]
[REGION_COUNTS:HILLS:300:0:0]
[EROSION_CYCLE_COUNT:250]
[RIVER_MINS:15:15]
[PERIODICALLY_ERODE_EXTREMES:1]
[OROGRAPHIC_PRECIPITATION:1]
[SUBREGION_MAX:5000]
[CAVERN_LAYER_COUNT:3]
[CAVERN_LAYER_OPENNESS_MIN:0]
[CAVERN_LAYER_OPENNESS_MAX:50]
[CAVERN_LAYER_PASSAGE_DENSITY_MIN:50]
[CAVERN_LAYER_PASSAGE_DENSITY_MAX:100]
[CAVERN_LAYER_WATER_MIN:25]
[CAVERN_LAYER_WATER_MAX:50]
[HAVE_BOTTOM_LAYER_1:1]
[HAVE_BOTTOM_LAYER_2:1]
[LEVELS_ABOVE_GROUND:10]
[LEVELS_ABOVE_LAYER_1:5]
[LEVELS_ABOVE_LAYER_2:1]
[LEVELS_ABOVE_LAYER_3:1]
[LEVELS_ABOVE_LAYER_4:1]
[LEVELS_ABOVE_LAYER_5:2]
[LEVELS_AT_BOTTOM:1]
[CAVE_MIN_SIZE:25]
[CAVE_MAX_SIZE:50]
[MOUNTAIN_CAVE_MIN:12]
[NON_MOUNTAIN_CAVE_MIN:24]
[ALL_CAVES_VISIBLE:1]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:6]
[TOTAL_CIV_POPULATION:800]
[SITE_CAP:80]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:0:0:0]
[RAIN_RANGES:0:0:0]
[DRAINAGE_RANGES:0:0:0]
[SAVAGERY_RANGES:0:600:0]
[VOLCANISM_RANGES:0:600:0]
Those parameters give me a world that's bright cyan and magenta, with all four civs + kobolds surviving to year 1000 90+% of the time.
"Desired Good/Evil Square Count in Small/Medium/Large Subregions": You want the values as high as you can get 'em without breaking worldgen. I've also fooled around with civs--fewer of them, and smaller. In previous versions, having a lot of good/evil land open for elven/gobbo population explosions could result in too many civs getting wiped out, esp. if you let worldgen go on for a long time.
"Maximum Number of Subregions": 5000, the max. It makes for a deliciously fractal world.
ETA: Oh, and necro towers? Anyone? The one thing those parameters aren't getting me regularly are towers, and that makes a sad mel.