I'm not sure exactly what you were responding to. I was mostly explaining that the ability to pick your companions as the lead character inherently takes away resources from writing the lead character or even fleshing out the companions themselves, because let's face it, the DOS2 companions had virtually zero character development and you were just along for the ride (maybe only Sebille and Fane had any actual development, but only because both actually had to make major choices beyond 'shank their nemesis' in the second half of the game).
None of the games you listed have that ability, if anything I am in agreement with those. Unless your message was more directed at someone else or the general crowd rather than me.
Still, if you want to talk about potentially losing party members like in DA2, then Pathfinder: Kingmaker is probably the poster child for that. You get the option to kill the majority of them as soon as you meet them. Failing to resolve their personal quests leads to them dying in the endgame chapter. But those deaths are for actual personal plot reasons, and they don't die offscreen.
(While controversial, it's subtly brilliant. The villain by that point recognizes that your companions are a big reason why you're able to oppose her so effectively, so she tries to kill them one by one in front of your eyes as you arrive to rescue them, by taking advantage of any momentary weakness in regards to their personalities and doubts. Like how you eliminated her chess pieces one by one throughout the entire game. She doesn't say this outright, but it's heavily implied because one of the prior companion quests involves one of her mooks luring out the companion and the main character alone, with the primary objective being to kill the companion, and that getting the main character in the process would be a bonus.)
Then again, that game was also one of the few that really nailed down how brutal a fantasy setting can be, with evil playthroughs actually BEING evil instead of just being an asshole. I had to give up my evil playthrough about a third of the way into Kingmaker because I legitimately couldn't bring myself to continue on with it (though I probably should have gone lawful evil selfish extortionist type instead of chaotic evil). That game had no voice acting for the main character, but it was really good at making your main character feel like an actual character instead of a mere observer.
Especially since you don't have to game some approval system bullshit when talking to your companions either, which is another thing that I've come to recognize as heavily hamstringing the writing of whatever RPG that has that system in the long run.
Except that it doesn't? There's only one that can be the PC, so they all have to have their stories fleshed out, because it's also possible that none of them will be, and it's hard to predict who's story will progress beyond the EA zones. Because of this, they have to write them all as if they will, because all of them will, even if it's not in a single playthrough. You may like different comps than I do, for example, and we may both bring different people through, although I'm not a fan of that particular aspect.
The message is: The comps have to be written out as if they'll all see endgame, because they all will, over the course of everyone playing it. The custom PC is, and should be, a blank slate. The story of that character isn't mired in who they were, but in who they are going to become over the course of the game's story, so our "custom" story is the game's narrative.
Pathfinder and ME 2 then, which I did list. There's even a critical moment in NWN 2, where certain comps can turn on you. The approval system exists, even in games that don't lean on it very hard. If there's a moment where a comp can be turned against you, but it fails because you did their personal quest, you're benefiting from the approval system. I much prefer when I don't know where it is, it seems more realistic that way, but that doesn't mean it's not there.
But yes, generally speaking, the writing being done on the Origin characters here would have to be done even if they weren't available as the PC. Since a custom PC, that isn't making a custom party of their own, will use some of them, they need to have that work done regardless, and it's not a "we'll just wing it" kind of thing. They all have defined stories running, and the defined story for the PC, when it's custom, is the game itself.