Dr Fallout
Centurion
That's really the issue with even many of the main characters.I really wanted to like Cait but her story pretty much starts and ends within an hour of meeting her.
Compare these companion characters to any character you meet, even in the smallest encounter, from Witcher series, Mass Effect, Dragon Age, Fallout New Vegas, Pillars of Eternity, Wasteland 2, or even Fallout 3 where you could at least ask characters about topics, and you soon realize just how shallow these companions really are. A dwarf blacksmith who gave me a one-off side quest in the beginning Witcher 3 had more going on than Cait.
Too many characters are cliches that I have seen repeated countless times. Mama murphy is a cliche of the standard drugged-up spiritual oracle you see in all sorts of fiction, Cait is a cliched drunk Irish stereotype, Nick is a cliche 1950s detective. They're all cliches. Even the gangsters in the vault where you pick up Nick are a bunch of cringe-worthy cliches that had me quitting the game at how out of place they all sounded. Why were there a bunch of gangsters looking and sounding like that? To be silly? Just for funsies?
In the end it doesn't matter because the companions are just there as pack mules for when you have to go clear out Corvega Assembly Plant for the 5th time because your settlers at Sanctuary Hills are very adept at getting kidnapped the second you leave.
Tell me about it, loads of other games have so much more character writing and stories even if they have less participation or aren't as important.