- During the game, they should have a predefined list of things to say, like in BG1/2.
-> The trigger to those sentences could be, i.e when you click on a portrait, or every 10 real time minutes. They could have things to say related to their personnalities "I like the smell of flowers" or "I hate this sunny sky".
-> They could also have things to say when they hit or kill an ennemies or when they are hit or killed. "HahahA see you in hell" "Take this !
I've heard a few comments of the first kind, so they're not completely absent. Most of the unsolicited comments are more situational though, like one of them saying they hear singing outside the cove, as a cue that something is about to happen.
The second type of comment, or "bark" related to combat can get annoying when there isn't enough variety. And there almost never is in games that use it, because voice acting is expensive. Every time I revived a certain main character in Wasteland 3, she would say "Woah, did I pass out for a minute there?" It was fun the first couple of times I heard it, but got old pretty fast.
What it comes down to is basically a complaint that I wish they had more money to pour into the game. If there can't be a huge variety of different barks for each companion so I'm not hearing so many repeats, I'd rather not hear them at all.