I must say, I did really like Arefu and the series of killings carried out by The Family.
Overall it's a well paced quest, and feels like a good self-contained adventure. The idea of a secret cannibal cult terrorising a small town is fairly small in scale, doesn't affect much, and overall fits the pulpy theme of Fallout quite well.
If this was in any other game, I will honestly say I would have liked it. The only flaw is that like everything in Fallout 3, it's held back by taking place in the nonsensical Capital Wasteland.
I actually hated Point Lookout. I hated the characters, the story, the fact that most enemies were bullet sponges and making me stretch my suspension of disbelief more then I care to. The only good thing about it was the environment. I liked the spooky swamp environment. Will give Bethesda credit with that. They are good when it comes to environments.
I sort of agree with you, and this might just be my nostalgia talking, but I've actually come around a lot on Point Lookout.
First time I played it I found it fairly barren and uninteresting, a small handful of Swampfolk and not much else. I also had minor gripes like the Point Lookout Tribals cultivating fruit in the middle of a church rather than in a garden, which felt typical of Fallout 3 using symbolic locations rather than pragmatic ones.
I've kinda come around a lot on it though. I actually quite like Desmond and Calvert's rivalry, it's corny to the point of ridiculousness with Calvert being pissed Desmond took away his body, but hey, it's a pulpy setting and it's kinda cool.
I also like this idea of "The Great Game" where all these pre-war aristocratic families treated their competition with each other as almost a game, and have figured out ways to prolong their lives to play this game even after the war. Maybe if Desmond wasn't a Ghoul, but rather just someone who underwent experimental medical treatment I would have liked it more, and I liked Calvert's goal to conquer Maryland by portraying himself as a living God.
I liked the Lovecraftian influence with the swampland being occupied mostly by cults worshipping eldritch gods, some explainable, some not.
Initially I was kinda apathetic to the Swampfolk. I liked how they had their own internal culture, and how they aren't just straightforward orcs like Supermutants: they trade with outsiders, and you can speak to multiple characters who were born in to that culture getting more insight in to them.
What I initially disliked is that they're kinda just dehumanised rednecks, devoid of actual human motivations which is dissapointing. I like humanoid antagonists to actually have goals and aspirations, and don't really like killing sentient people for no reason.
In hindsight however, I realise they're inspired by both Deliverance and Shadow over Innsmouth, and in both cases they fit what they were going for pretty well: the horror of being chased out in the middle of a rural area where nobody will ever find you.
In the case of Shadow over Innsmouth, I can't say the Swampfolk don't fit Lovecraftian Horror. To a certain extent all Lovecraftian Horror is based on some degree of Xenophobia in the literal sense of the world(Appropriate for the man himself).
Like Shadow Over Innsmouth partly works as a horror precisely because of HP Lovecraft's Xenophobia, because it's set in an incestuous New England fishing town, whereby the locals could be up to anything behind closed doors, and Lovecraft is clearly deeply suspicious of people like that, and later works in the same genre, such as, say Stephen King's mist, the horror is in these urbanites trapped among these rural people who, in the face of eldritch horrors, turn to barbaric cults based on human sacrifice to stop the end of the world. Both of these are in a sense, based on a horror from Othering groups of people, and the horror comes from this Xenophobia towards people the authors view as simple.
While I feel this could leave room for more critical discussion, I can't say the vibe of othered rural people with lovecraftian practices you don't understand being evil isn't appropriate for the genre, and it's a fairly good encapsulation of what Lovecraftian horror is.