First off, it depends what you mean by fanfic?
“Fanfiction” gets used pejoratively a LOT (a la My Immortal), to demean its quality; usually by people who act like fanfic's nothing but gay/smutty self-inserts; or that just cuz fics are self-published that they can't be peer-reviewed (a la beta readers); or that just cuz most fics are written by unpublished "amateurs" & recreational hobbyists that they can't be well-written.
Even though there's thousands of fic authors who write WAY better than published authors. Even though there are professional authors who started out as fanfic writers (e.g. Shadowhunters' Cassandra Clare). Even though professional authors have been known to even use pseudonyms to write gay/smutty self-inserts--a la Anne Rice herself (aka Anne Rampling / A. N. Roquelaure). Look at 50 Shades, which started as just a fanfic of Twilight b4 someone in Hollywood read it & liked it enough to adapt it into a movie (curse them).
I've been in fandoms where the fanon is WAY BETTER than the book/film/show canon (*cough* Teen Wolf *cough* 😒). The "Fix-It" tag & "Alternate Universe - Canon Divergence" tag exists for a reason, cuz sometimes the canon is TRASH, and people's headcanons work BETTER. When an adaptation ELEVATES the source material, who cares if it's self-published fanfiction or a Hollywood production, so long as it's GOOD? 🍻
Hell, even the IWTV movie ignored a lot of canon.
Where's Louis' siblings (X X)? Where's Babette (X X)? What in the heterosexual "wife & child" was Louis talking about?! Where was Lestat's dad? It wasn't gay enough. Where was Antoine? Why was Loumand's part so dang brief? Why TF did the Botticelli angel Armand look suspiciously like Antonio Banderas in a Morticia Addams wig? Why was Louis' hair BROWN when it was supposed to be BLACK? Isn't Lestat supposed to be TALL? 🤨 Etcetcetc. (A lot of this the show actually FIXES!)
Claudia was aged up from 5 to what? 12? Only for AR to create a very high-functioning preteen vampire with Benji in TVA--thus highlighting just how important it was that Claudia was supposed to be FIVE. A toddler. IMAGINE: a 5 year old's head chopped off and sewn on a grown woman's body. Not 10 or 12 or 14 or 19--FIVE. That's the Claudia I'm still waiting to see on screen--THAT is a monster. But Kirsten & Bailey & Delainey are STILL killing it, regardless.
And wasn't Lestat a "typical evil man" when he jumped Daniel?
Some fans were tickled by the film changing the ending, while others HATED it. It not only made Lestat "OOC" (hijacking Armand's role as Dan's Maker but WORSE--cuz if the film implied that Les turned Dan into a vampire then that scene was a RAPE--a la David in TotBT), but it just straightup NEVER happened. Headcanon much?
As for abuse, BOTH the movie AND the show actually REMOVED/SOFTENED a lot of the physical fights--not just the DV b/t Loustat, but also the child abuse against Claudia, where Lestat often tried to hurt her & Louis.
We all squee at how cute it was that Claudia & her Daddy Lou shared a coffin, but neither the film nor the show mentioned that it was actually LESTAT who told her to sleep in Lou's coffin in the book--cuz it came with a THREAT against her. And Les threatened her A LOT:
Louis had to get between Les & Claudia & fight Lestat off of her--even the most graphic fight Loustat had b4 she was turned was still over Claudia.
Which was why it wasn't surprising that the big fight in Ep5 was also over Claudia, as Lestat attacked her and Louis had to get in the middle & fight him off. Sure, it's tweaked on the show, and framed more explicitly as spousal issues, but it's not purely a headcanon that came from thin air.
The show is ELEVATING the source material. Some people DON'T want another 1700s slaveowning plantation antebellum vampire universe; don't want subtext; and want to see things from the book EXPANDED on in fresh new ways.
Claudia's backstory is "made up" cuz she never had one in ANY of the books! Louis' family dynamics are expanded but they're NOT changed--Paul & Louis' sister are BRIEFLY in the books, but AMC stays faithful to Paul's religiosity and Louis loving his sister, while giving them more space to be fully fledged and absolutely amazing & complex characters who are only ENRICHED by the show--Paul was only in ONE episode and he made a massive impact on the fandom.
This is an adaptation--to adapt means to CHANGE. What point is there in saying "they shouldn't have changed so much" and then claiming you liked the show, meanwhile complaining about everything that they made better?
