Also, different races have different stat averages. Dorf's tend to have things like higher creativity than average (lots of creative dorfs, few with negative attribute). I'd imagine elves might be low on strength, but high on agility. This would allow you to better specialize labor. Your ranged squads could be all hippies (high agility). I believe goblins have decent agility and -very- high memory.. which should make them good herbalists and back up archers. Goblins DO have a high rate of murder in their civs though... so likely any goblin refugees would just wind up in jail. Not sure what the stat averages for humans are.
The pluses and minuses about to be mentioned are a system of standard attribute ranges where one plus is plus 250 to each spot on the range and one minus is 100 less to each spot on the range.Dwarves have a plus to: strength, toughness, analytical ability, creativity, patience and memory, two pluses to focus and spatial sense, and a - to agility. Humans have completely average stats as they are the basis for the stats, they are a good bit bigger though. Elves a plus to: agility, recuperation, intuition, spatial sense, musicality, empathy, and social awareness, two pluses to kinesthetic sense, three pluses to disease resistance and linguistic ability, a minus to patience, and a memory as high as it gets. Goblins have a plus to: strength, recuperation, and disease resistance, two pluses to: endurance, willpower and social awareness, two minuses to creativity and intuition, three minuses to empathy, and a memory as high as it gets.
I'd say agility is probably better for melee combat than archery though. Agility affects movement speed which barely matters for archery, and it affects all combat skills of which archery has two, and melee has six. What elves would be best for it seems, is brokering. Elves have incredibly high linguistic ability to the point where the worst possible linguistic ability an elf could get is still a good amount better than the average dwarf. Then their high memory helps them remember those skills since brokers commonly have long breaks before caravans. Overall I'd say elves are slightly worse soldiers than dwarves, though they do have a very high memory and no maxage so that helps slightly. Goblin stats are quite bad for any creative labors, but they are about as good, maybe slightly better for combat than dwarves' then you throw in their high memory and no maxage and you got a soldier that's better than a dwarf. Humans don't have any bad stats, but they also don't have any good stats and since all the others have almost exclusively positives and humans have a by far lowest max age of 60:120 they don't seem very good. However, they do have one advantage, and that is size. Size gives them a significant better wrestling defense and offense, along with a general strength increase that probably makes them equal to goblins in strength. Size also allows them to wield bigger weapons, those being the two handed weapons, and it guarantees that every human can use the smaller weapons in one hand, while some of the others might need to use two. So humans would probably be better for wrestling and two handed weapons should you find some good ones, and I've heard stories that the two handed sword is incredibly powerful so it might be worth it.