In my simworld, premades have generally had an awful time of things, because I tend to see them as fair game for all my most devilish gamer instincts. A great many of them, I've merely killed off to free up a lot; often that lot is then demolished and turned into ordinary housing (my standard Levittown-esque sim box built for practical efficiency.) Others, I've edited in CAS to the point where they're unrecognizable as their original premade form; Jessie Charbonneau, for example, a sim well-known to people who read my "what happened in your game" posts, started life as Miko Ojo and got a CAS makeover into everyone's favorite French-Canadian sweetheart of a celebrity chef.
The ones I haven't killed, well, some have fared better than others, but others have suffered utterly cruel fates.
Cassandra Goth, in my simworld, is a "woohoo worker"; after she aged up, her gloomy adolescence turned into an outright nihilistic dance in adulthood with hedonism and desperate attention-seeking. Probably for the best that drugs don't exist in the Sims without mods because she'd probably have ended up like Jane from Breaking Bad by now. She remains the most convenient way single male Sims have of quickly reloading their Fun and Social needs when they're skilling up and advancing through their careers before getting married.
Malcolm Landgraab, in my simworld's canon, is a pariah. He had an...incident...involving a young girl (completely offscreen, of course), but his rich parents' connections allowed him to escape justice. Every sim in the world hates him, none will speak to him (and if they do, it's to insult and fight him), and he must forever live with a punishment greater than prison—his own utter isolation and perhaps just a tinge of regret. I'll probably kill him off eventually but for now he's a great punching bag for everyone else.
Geoff and Nancy Landgraab, meanwhile, have an utterly toxic marriage held together entirely by money. Many female sims in my world consider it a rite of passage to woohoo with Geoff upon moving into their first home, and he's got an in-world canon rivalry with Don Lothario regarding the subject...one Geoffrey is winning. Nancy, meanwhile, tried to get her revenge on Geoffrey by doing some cheating of her own...and instead ended up pregnant. She's raising a daughter, effectively a single mom in her own home, and Malcolm is not allowed to interact with his half-sister due to his reputation. The Landgraabs would've divorced long ago but for the fact that money and a big enough house for them to stay out of each other's way makes theirs a marriage of convenience.
Eliza Pancakes had a similar problem as Nancy, though in her case, she thought Simo Koivonen—the dashing Finn who is the father of nine children by seven women and who died when he froze to death in a malfunctioning shower on a scorching hot Oasis Springs summer day—loved her. He didn't. He just wanted to sow his seed, and Eliza bore him a son, Hugh Pancakes, who has never seen or known his father. She is raising him alone in the house she inherited from her late husband. The boy's destined to become a short-order cook someday, I suspect. "Huge" Pancakes? What a name. The game gave it to him when he was born offscreen.
Bob Pancakes, as the previous implies, is dead. He took his own life by putting on his winter clothes, driving out to the cemetery in Oasis Springs during a heat wave, and lying down watching the clouds and waiting for the Reaper to take him, which Grim duly did scarcely an hour later. At least he died quickly, in a contemplative mood. May the next life serve him better than the one he lived on earth. (Narrator:: It didn't.)
Don Lothario, however, is more of the wannabe Casanova. He's more Johnny Bravo than anything. Fit, muscular, conventionally good-looking...and women tend to be repulsed by him because he has absolutely no tact whatsoever. I found it funny to turn a guy with a propped-up-by-the-game reputation as a great lover into a cartoonish buffoon. He still succeeds sometimes—the game is quite accommodating of ham-fisted romantic efforts if the target's sufficiently flirty—but he often ends up awash in yellow moodlets. Shameless flirting with Unflirty sims who will never reciprocate is its own form of comedy.
Not everyone came to a bad end (or got edited beyond recognition as a premade.) There have been a couple of happy-ending stories for premades:
Diego Lobo, I decided to give a makeover to, but it was purely a plan-outfit rather than change-sim makeover. In-game, he got a crush on his gym trainer who rejected him on grounds that she preferred her men masculine in the old-school sense. Diego, besotted, got rid of his silly hairstyle, his makeup, and his Riddler wannabe outfit and underneath was an incredibly suave Latino who frankly impressed me with just how complete the transformation was. His wife died of old age, and before Diego himself departed the world, he had a son by his second wife, named Hernando, who is getting his own story (soon as I get back to playing regularly—I've been playing and completing The Witcher 3 for the past week or so) in the world. The young second wife eventually woohooed Diego to death, incidentally. What a way to go.
Raj Rasoya is happily married despite being unflirty; after the death of his mother Geeta, Raj met a woman at the karaoke bar who became the love of his life. She's a big girl—"yo mamma so fat, every time she sings, the opera ends"—but that just means she gets to eat more of Raj's delicious culinary creations.
And Johnny Zest? He moved out of his trailer, marrying a woman of my creation, a green-eyed redhead named Caitlin O'Brien; the two are happily married, and Johnny's former home is now a lush desert garden/farm owned by one of the Koivonen Kids, Anna Trevino (daughter of townie librarian McKinley Trevino, who now works as an Investor in the business track.)