I've just completed 5 years with this mod (0.40.xx experimental) and I guess it's time to report.
Playing the complete install. Basic worldgen: Large world, Very High sites, beasts and savagery. 250 year history.
That left all the races intact, there was even 1 Dwarf civ left (out of 5) with a healthy population of just under 2000.
I embarked in the most Fun looking location I could find. A long, long way from the other Dwarf sites with neighbours of: Fiend Spiders, Badgermen, Raptormen, Tigermen, Warwolves, War Elephants, Pandashi, Jotunar, Frogmen, Hellfire Imps, Dark Stranglers and Goblins. There were Humans and Elves around someplace too apparently, but they never turned up in the five years of play.
Year 1: Quiet. Population 27 by the end of Autumn
Year 2: Werehorse attack in Spring. Turns out to be a War Wolf. Werehorse Warwolf. Hmm. Interesting.
Population 69 by the end of Autumn. Gave traders massive profits and sent millions in tribute to mountainhome.
FB attack. Giant Bee. 1 Dead guard. Mayor lost a hand. One chap with advanced rot in the lung - seems to be OK.
Year 3: Spring migrants bring the population to 91. Attacked by a giant. FB in the caverns in Autumn and then...
Winter Goblin siege! Yay! 10 goblins. Swordmaster wiped them out. Military training OP...?
Year 4: Spring - Dark Strangler Siege! 9 monkeys and a kobold thief caught in the crossfire.
Summer - War Elephant thief failed to sneak into the fortress was chased by one of the crossbow squad...
who ran into a Goblin Siege! 35 goblins and 9 trolls.
Autumn - Bit of a break to give loads more gold to the traders to encourage bad people to come visit.
Winter - White Tigermen Siege!!! Bit of an anti-climax, they showed up and left right away.
Year 5: Spring - Frogman thief. Not falling for this one again. Leave him be and sure enough...
Dark Strangler siege! 31 Dark Stranglers. The swordmaster strolled out to meet them
...and ran into a Pandashi Ambush! An ambush, in .40.24!!?? Wonders never cease.
Approaching the Pandashi and.."A horse has sprung from ambush!". Um...OK
Altogether about 50 Pandashi were hidden out there and two evil horses. They all ran away
when they saw the swordmaster approaching.
Summer - Great Fiend Spider Siege! 10 spiders. Unstoppable forces of evil and..."I was attacked! How shocking!",
"Gruesome wounds...begone fear". Not quite as scary when they start talking. Interestingly the siege included
3 Great Fiend Spider Crossbowmen. Luckily they seem to have left their crossbows at home.
Autumn - Goblin siege! 42 goblins
Winter - Dark Strangler siege! 39 Dark Stranglers.
And that's where I left it. Basically an attack every season starting at year 2 winter. Hopefully the Spiders are coming back in force next year. No hellfire imps, Badgermen or Jotunar yet.