I'm also in favour of Pirates and Castaway.
The most important point is that the game delivers an interactive setting with the story being a secondary addon. That's why I think finding someone or a murder story would be bad choices. Because once you've found the missing person or solved the murder case, what is there left of the pack? Crime & Hightech is more versatile. There can be a specific crime that makes up the story, but once we've solved that, we can still have fun with gangs, FBI agents and inventions.
Kinda like Strangerville - you can stay in stage 2 or 3 and create an immersive save around the situation without ever needing to touch the story again. In a murder story staying in stage 2 would be boring, because that wouldn't be any different from a normal sims game.
With pirates I could imagine:
stage 1 = pirate sightings, pirates visit the town but are more chatty than aggressive, they sell exotic goods (spices, parrots) for rum (new harvestable: sugar cane, new crafting station: sugar press)
stage 2 = the town under siege, random attacks of spys
stage 3 = the town under attack, regular burglaries, aggressive pirates in the streets
So, each stage would be distinct and interesting without the need to advance the story.
