Your #2 isn't so much a "writing" thing as a simple design choice. If what you want is more spaced out romance dialogues, all it takes is a few lines of code to check for story progression before triggering dialogues/events, combined with longer timers between dialogues/events. You're not saying anything about the actual quality of the writing in the games you've played.
Same for #3, it's more a game mechanics than writing. Basically you want a mechanics that allows party members to change their alignment over the course of the game? So they can never hate you and leave you? Far as I can tell, we don't simply "change". From good to evil or vice versa. It'd take major life events for such changes. I suppose we can do such a thing for one or two select companions like in BG2, sure, but for everyone? Otherwise, how do you propose we implement this kind of mechanics? Are you suggesting that we should be able to "mold" anyone's nature simply by having them follow us? Would people simply change from good to evil or vice versa just because they're tagging along with an evil or good character? Chances are what they'd do is they hate you and leave you.
Despite the topic title, you're not "suggesting" much. You're mostly stating what you like or dislike.
No, it's not about timers or spacing out the dialogues. It's about adding more dialogue and cutscenes than there were in the previous games. As for #3, the writing is supposed to reflect the change in mechanics. In a way, the characters' fates would be inextricably intertwined with those of the main character. Major life events occurring in the lives in the characters would be a fine addition to BG3 in my view. That aside, I do believe your nit-picking is uncalled-for. I wasn't going to write a 1000-word essay laying out my vision for the story from start to finish anyway and I'm not going to play your little semantics game.
EDIT: Imoen is the protagonists' sibling in the BG saga so not all companions have to be people you pick up at the tavern or on the street who will leave your party at the drop of a hat. I'm sure that's who you meant though.
Re. alignment, and saying up front that I have always disliked the D&D alignment system, to me being evil should not necessarily mean such a companion will automatically leave the party just because the party as a whole is good. An evil-aligned person can and should still feel that they want to remain in the party if they feel the party is continuing to serve their interests, interests that include staying alive in a world that is hostile to you. The system is rather simplistic and superficial if all that it is is to say: if you're "good" and I'm "evil" then I'm outta' here. Peoples' motivations are always way more complex than that. And writing characters with complex, complicated, deep motivations *is* about the quality of the writing.
Thank you, sir.