Random is random, random is random. You can insert 'love' and 'life' wherever you want in the previous statement; that's the glory of random! I'm a fan of random elements and random-gen, so I'll toss a couple ideas out:
*Random animal siege: for whatever reason an ecosystem has destabilized and led to the rare mass migration of a randomly selected creature.. Between 10-50 of the chosen creature shows up and generally tries to path either east-to-west or north-to-south, crossing the map to continue on in their 'migration' direction.. Fifty rabbits hopping through is nothing.. A blend of fifty (normal sized and giant giant sized) cobras suddenly showing up in force is another thing entirely..
*Ancient dwarf arrival: A dwarf near the end of their lifespan (within one to five years of natural death) arrives at the fort with one useful legendary skill and very high social skills. The randomness comes from a 5% chance that the elder is a werebeast or vampire (10% chance total), a 10% chance that the dwarf is senile and
will have a dangerous breakdown before death, and a 1-3% chance per day (or half-month?) of going senile.. They have the high social skills so they have the ability to quickly bond with your fort-dwarves and generate sadness when they inevitably die.. They should probably generate with as many 'retirement'-simulating emotions/characteristics as possible, in an attempt to reflect that they came to your fort to be happy and socialize after a long and redundant life of labor.. They
will work, you could make your ancient legendary weaponsmith craft weapons, but due to their old/tired bodies and general hatred of their profession they'll get strong negative thoughts from labor.. All those threats combined should balance out receiving the single legendary skill.. Of course you'd also need the ability to turn them away, if the risk of accepting a vampire or werebeast (or unstable old person) is too high.. ((**Lots of "guests" would be pretty cool, with risks and rewards similar to this.."Reformed" goblins, bands of stranded elves looking for temporary shelter, a group of human "businessmen", all with potential good intentions or potential hidden agendas..))
*Tyrant-king: Ideally you'd want a pre-embark option to toggle this stuff on and off.. Anyway, this would give a 25% chance that any dwarven ruler is a tyrant and will make wild demands/tribute from your fort-dwarves, and will wage dwarf-on-dwarf war if demands aren't met.. It'd basically be "uber-mandates" for things like 100 barrels of booze, or twenty-thousand urists-value of prepared meals, or 25 pieces of armor or weaponry,
important stuff.. If you purposefully ignore the mandates a couple dwarf-sieges will show up before the king shows up himself, and of course, historically, a beheaded person makes no mandates
As a benefit of regularly meeting the mandates, though, the king could send some of his best warriors to defend his "asset", with the potential of friendly legendary fighters showing up.. Then again, failing the mandates and having the tyrant's branch of the civ go hostile would ideally turn any on-site entities hostile..
*Artifact salesman: All well and good, if the shiny bauble he offers (but won't show you pre-purchase!) actually is a real artifact, and not a chicken-bone totem.. Basically DF's version of the unidentified item salesmen on Diablo..
Some randomized embark item selection would be good in addition to the fully randomized embark location (I guess you'd just choose embark size), maybe some themed choices like 'Weapon Merchant' or 'Herder' or 'Traveling Chef', that'd give you a randomized selection of weapons, or animals, or food.. Whether or not you've got a pickaxe or wood-cutting axe are pretty important for most embarks, though, so an option that always gave an axe/pick/anvil in addition to a randomized loadout would be friendly..
It'd also be interesting to be able to alter the 'dwarven tech tree' by completely disabling entire industries at worldgen, except for brewing booze.. Play a version of dwarves that don't know masonry or carpentry, or that only knows masonry and carpentry :> A mode that awards you with "new technology" over time, or based on discoveries or achievements.. Or a random-selection mode that unlocks one workshop every half-year..
I keep wanting to suggest random stone/material generation, but you'd have to do it without devaluing steel and candy.. I'm thinking of rock or metal laced with good, bad, and neutral syndromes, along with any and all currently available stone properties (without devaluing the high-end vanilla materials, again).. Rock that expels smoke or dust, or the equivalent of infected organic matter that releases germs when destroyed, blight/mold/rot effect that spreads over time.. And then you'd need From what I understand a lot of framework is missing for how these things interact with dwarves (things that will only work by injection, for example) for most of this, but I don't expect any of this to get implemented (though I'll hold out some hope for migrating animal hordes.. I'm not even sure I like the random stone idea myself)