I believe the companion characters should be explored more, my connection to the diamond city radio guy is stronger and he feels more real because he actually updates his stories whenever you've done something for the commonwealth whereas your companions say the same stuff like Piper Wright for example "Never thought a reporter could consider themselves a success until someone threatened their life. Me? I'm very successful." I hear that quote on pretty much every quest and it degrades her characters realiticity
When I first met Piper, I thought that she would have a whole line of quests lined up for me and a strengthening storyline to really make her character mean something. Of course there is the romance system where she tells you her life story but my sympathy for her problems isn't there because I'm just objectively waiting for the option of romance. The only emotion I ever get out the romance system is an awkward creep vibe, like take Curie for example. I really want to help her reach her objective in Science but the romance option fully seems to take it away from her and seems like I'm being an unfair character.
Going back to character development, I believe with Piper, there should be a line of storyline epic quests to which the final reward earns the companion, of course some quests involve her as a temporary companion but not all of them. Ideas for quest lines might involve escorting her through dangerous places to get the top notch interview for her paper. This way the relationship is strengthened, or at-least have good quests specified for the characters during companionship. I believe that this was done right with Cait where after a while you can help fix her, perhaps it might have been a bit of a stronger storyline to start her off as a drug decayed looking character and then after the quest to fix Cait she becomes vibrant but idk thats just me.
When it came to Piper, I felt like she was going to have a big impact on the storyline atleast within Diamond City given her reputation but that one interview quest takes place and now she no longer really plays a part at all. I believe Piper could have been a character that very few people took an interest in and took her for a bad conspiraciest and then you help build her storyline and then after you've done her all that you are rewarded with the option of romance and the end of her quest line also results in the 90% of people thinking wow she's amazing and then the 10% haters give insults to which she sits them on their ass with a comeback that isn't too aggressive but similar to Neil Degrasse Tyson proving to B.o.B that the earth is not flat.
To top it all off quotes should really be updated enough to keep a good connection to the character, atleast enough quotes so that it doesn't sound too repetitive. Hopefully Bethesda takes this into future games, I know budget and deadlines make it tough, but its the little things that make a game greater than great.