I've always wondered, how do you make companion mods that don't suck or aren't cringeworthy?
Your character also has to fit into the context of the world, and feel like they belong in the world you're putting them in.
Like say, for instance, when thinking about a character to put into Skyrim, a good example would be a female Nord warrior who's all about Nord culture and its warrior-poet traditions. She'd be very adamant about Talos worship and worships the ground Ulfric Stormcloak walks on. If you want to get into her panties, you can just reflect Stormcloak talking points, but if you want to turn her pro-Imperial, you have to persuade her that the Stormcloaks are harming the Nords as a whole and even show her evidence of it. (ie. show her the Thalmor dossier that says that they're manipulating Ulfric Stormcloak, show her the Gray Quarter in Windhelm where the Nords treat the Dark Elves like shit, show her Markarth where the oppressed Forsworn are chomping at the bit for vengeance because of what Ulfric did, etc.) Then maybe you can get her to fight for the Empire or mate with you despite the fact you're pro-Imperial.
Outside of the mechanical level, a New Vegas companion is essentially four components: A personality and worldview, a companion quest, a backstory that explains the former and presents a problem or regret for the latter to solve, and a voice that ties it all together.
Take for instance Boone. Boone is a broken, depressed shell of a man mostly just moving on autopilot and his hate for the Legion. His backstory is that during his time as an NCR sniper he did some fucked-up shit that left him believing that the only justice for him could be a lonely, miserable death, and the moment he began to find a way out of his pit, it was all snatched away from him one last time. His companion quest is handled in two parts: earning his trust, after which he opens up with the gory details of his story, and then helping him to reconcile with his wrongdoings and find the strength to keep moving forward (unless you're an asshole). And for all of this, it still could have collapsed into a worthless pile of edge if not for the phenomenal work of
Jason Marsden, who sells every ounce of sorrow and regret his role demanded.
If you want to make a good companion mod, start by making these four parts work together as well as possible, and you should be off to a good start.
Part of what made Craig Boone such an awesome addition to Fallout New Vegas is that not only is his character deep and nuanced, not only is the backstory for him tragic and sympathetic, not only is his VO one of the best, but he also fits in the context of that world. He was engaged in the wars of the NCR and dropped out because the NCR forced them to keep attacking even when the enemy before them were just women and children. Then there was the stuff that happened to his wife, which involved the Legion. And you can gain his trust by having him fight the Legion, which then ends with him opening up to you and going to a place familiar to him, where the two of you turn the tide in a skirmish that becomes widely known as an act of heroism. And all of this fits into the context of the Legion-NCR War which was at the heart of New Vegas' story.
Instead of that, we have the girl named America in the Frontier DLC, and having a naive, easily-broken, easy-to-trust girl like America in a crapsack world like Fallout, hanging around with the Brotherhood Crusaders after parents abandoned her, doesn't make any sense. Would the opposite not occur for her? Wouldn't her experience teach her to not be so easily trusting, to not easily open up to the world? Wouldn't that make her instead into a jaded bitch who hunts down Brotherhood Paladins like scum because the Brotherhood of Steel wanted her gone for being a mutant, and her parents from the Brotherhood abandoned her to die? Her being a naive girl who easily trusts you and who hangs around with Brotherhood-style organizations like the Crusaders doesn't make sense.
It'd make more sense if she was riding with some kind of Enclave remnant that picked her up, and she's OK with them experimenting on her mutant body long as they give her the chance to wreak brutal vengeance on the Brotherhood and her parents for expelling her, essentially turning her into a female Frank Horrigan. She'd be walking around with a custom set of Enclave power armor, and you see her gunning down Brotherhood Paladins who have surrendered while asking them where her parents are. You can even add in that she abandoned the name her Brotherhood parents gave her, and she named herself "America" in honor of the Enclave for allowing her to join them. Then you can have her be a character who joins you if you join the Frontier Enclave, and she's assigned to you by the Enclave leader to A) make sure you succeed and B) kill you if you turn disloyal. And her loyalty mission would involve her finding her parents from the Brotherhood of Steel, with you getting her to kill them or spare them after humiliating them so she can get some closure.
But no, you can't have nuanced characters like that because the Frontier devs wanted their slavegirl waifu with stinky feet, and you can't join the Enclave because "it's a fascist power fantasy" even though they let you join the fascist Legion.
People today really are stupid.