i could picture goblins herding pigs, feeding them with the remains of their dead and war prisoners they wouldn't eat themselves, and pasturing them on the caverns
Now that you mention it, I remember Toady talking about herding in world gen being what he needed to work on before he made goblins have to eat. Somebody go look into the last couple DF Talks or FoTF posts by Toady to confirm.
And the problems with kobolds dying in world gen is caused by the lack of options in world gen, but next few updates will see more movement on the world map and eventually moving caravans to mitigate the extreme surplus/starvation cycles in world gen, as well as make it possible for kobolds to procure their food.
On the subject of zerg rushing elves and immortal goblins:
1. Goblins (in Tolkien) were corrupted elves, and thus are immortal, albeit a tortuous life. The most fitting comparison is Gollum's long life, aka a pathetic and painful existence.
2. Cannibal, immortal, only-wood-using elves with the actual repercussions immortality has on the populations, aren't trying to be Tolkien's elves. They are Toady's elves, and his vision is different than Tolkien's. The Dwarf Fortress elves are more nature-oriented, seeking to emulate nature in eating the corpses of fallen foes, or communing with animals. They are less civilized in the human sense because they embrace their natural instincts and bring themselves to the same level as animals. Animals breed rapidly, so do elves.
If you want Tolkien's elves, find or make a mod, it's why the raws are there. Vanilla DF can't cater to everyone's favorite interpretations of fantasy races.
I hope that cleared up some of the issues people are having with the currently unfinished and unbalanced world gen and Toady's design decisions.