No seriously, hear me out.
I've generated ten worlds and taken notes on each one. I used vanilla raws except letting every race be playable and giving humans a death god every time. I generated each world for 250 years, omitting worlds where one or more nations were inaccessible from the mainland. The average number of nations per race is 3, but the number varies. Kobolds were not included with the experiment because they don't matter. If you really want to know the rest of the settings they are below.
[WORLD_GEN]
[TITLE:SMALL ISLAND]
[DIM:65:65]
[EMBARK_POINTS:1504]
[END_YEAR:250]
[BEAST_END_YEAR:100:80]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:0]
[ELEVATION:1:400:800:800]
[RAINFALL:0:100:101:101]
[TEMPERATURE:25:75:101:101]
[DRAINAGE:0:100:101:101]
[VOLCANISM:0:100:101:101]
[SAVAGERY:0:100:101:101]
[ELEVATION_FREQUENCY:3:2:0:1:0:1]
[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]
[POLE:NORTH_AND_OR_SOUTH]
[MINERAL_SCARCITY:2500]
[MEGABEAST_CAP:8]
[SEMIMEGABEAST_CAP:12]
[TITAN_NUMBER:6]
[TITAN_ATTACK_TRIGGER:80:0:100000]
[DEMON_NUMBER:20]
[NIGHT_TROLL_NUMBER:8]
[BOGEYMAN_NUMBER:8]
[VAMPIRE_NUMBER:8]
[WEREBEAST_NUMBER:4]
[SECRET_NUMBER:1]
[REGIONAL_INTERACTION_NUMBER:5]
[DISTURBANCE_INTERACTION_NUMBER:1]
[EVIL_CLOUD_NUMBER:5]
[EVIL_RAIN_NUMBER:5]
[GENERATE_DIVINE_MATERIALS:1]
[GOOD_SQ_COUNTS:1:16:0]
[EVIL_SQ_COUNTS:1:16:0]
[PEAK_NUMBER_MIN:1]
[PARTIAL_OCEAN_EDGE_MIN:0]
[COMPLETE_OCEAN_EDGE_MIN:4]
[VOLCANO_MIN:1]
[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:250]
[RIVER_MINS:5:5]
[PERIODICALLY_ERODE_EXTREMES:1]
[OROGRAPHIC_PRECIPITATION:1]
[SUBREGION_MAX:2750]
[CAVERN_LAYER_COUNT:3]
[CAVERN_LAYER_OPENNESS_MIN:0]
[CAVERN_LAYER_OPENNESS_MAX:100]
[CAVERN_LAYER_PASSAGE_DENSITY_MIN:0]
[CAVERN_LAYER_PASSAGE_DENSITY_MAX:100]
[CAVERN_LAYER_WATER_MIN:0]
[CAVERN_LAYER_WATER_MAX:100]
[HAVE_BOTTOM_LAYER_1:1]
[HAVE_BOTTOM_LAYER_2:1]
[LEVELS_ABOVE_GROUND:15]
[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:5]
[CAVE_MAX_SIZE:25]
[MOUNTAIN_CAVE_MIN:2]
[NON_MOUNTAIN_CAVE_MIN:3]
[ALL_CAVES_VISIBLE:1]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:15]
[TOTAL_CIV_POPULATION:22500]
[SITE_CAP:400]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:136:272:136]
[RAIN_RANGES:0:0:0]
[DRAINAGE_RANGES:0:0:0]
[SAVAGERY_RANGES:0:0:0]
[VOLCANISM_RANGES:0:0:0]
And now the data:
World 1
- 29804 humans
- 20016 goblins
- 15138 dwarves
- 4392 elves
Notes: 2/3 elven nations gone, 1/3 dwarven nations gone
World 2
- 26957 elves
- 18035 humans
- 15931 goblins
- 117 dwarves
Notes: 3/3 dwarven nations gone, 2/4 goblin nations gone (an extra one)
World 3
- 25804 humans
- 16809 dwarves
- 11072 goblins
- 4097 elves
Notes: 1/3 dwarven nations gone, 1/3 elven nations gone, 1/3 goblin nations gone
One more elven nation is almost dead
World 4
- 31551 elves
- 27640 goblins
- 9654 humans
- 2958 dwarves
Notes: 1/2 dwarven nations dead, 1/4 elven nations dead, 1/4 human nations dead
An elven and a human nation are almost dead
4 goblin nations
Elves aren't really winning, there are a lot of goblin elves
World 5
- 22541 humans
- 17833 dwarves
- 15008 goblins
- 0 elves
Notes: 1/4 dwarven nations dead, 2/3 goblin nations dead
No elven civs were generated (no forests, just marshes)
World 6
- 22084 dwarves
- 20251 humans
- 12733 goblins
- 6000 elves
Notes: 2/3 elven nations gone, 1/3 goblin nations gone
Dwarves are winning only because everyone else killed each other
World 7
- 50901 humans
- 14512 goblins
- 5262 elves
- 4409 dwarves
Notes: 2/3 dwarven nations gone, 2/4 elven nations gone
One more elven nation almost gone
This world has 10 towers because a weasel woman necromancer founded six of them
World 8
- 33758 humans
- 10194 dwarves
- 5329 goblins
- 0 elves
Notes: 2/4 dwarven nations gone, 2/4 goblin nations gone
No forests again
World 9
- 22594 elves
- 19725 humans
- 15393 goblins
- 9894 dwarves
Notes: 2/3 dwarven nations gone, 1/3 elven nations gone, 1/3 goblin nations gone, 1/3 human nations gone
World 10
- 34566 humans
- 16005 goblins
- 12480 elves
- 12 dwarves
Notes: 1/1 dwarven nation gone, 3/4 elven nations gone
All remaining dwarves live in one hillock except a necromancer
Goblins attacked and destroyed a kobold cave
Average places
humans - 1.5
goblins - 2.6
elves - 2.625
dwarves - 3
Worlds with no elves at all were omitted from the elves' average.
Now, 10 worlds may not been a big sample, but these findings support what I've seen in other worlds. Humans usually "win" - they like to conquer the elves and goblins and take over their sites. Humans' varied personalities and values occasionally spit out the perfect general. Goblins tend to attack everyone and breed like rabbits. If goblins "win" it's usually because their master isn't a pacifist and leads his troops personally. Elves also breed like rabbits and if left alone can outpace everyone.
Dwarves never attack anyone. They only defend. Even then they usually take more casualties than the enemy - even if the enemy is
elves. A defending nation can only lose - if an attacking nation loses, they retreat and try again. If a defending nation loses, they're dead and gone.
Dwarves' sites are prone to FB attacks, and I have never seen an FB get killed in worldgen. Dwarves breed slowly, and an early megabeast attack on their capital can destroy their population expansion. Dwarves are losers in worldgen. This is the exact opposite of how they are in fort mode.
So now that the problem has been identified, what can we do about it?