People have been defending the current companions by saying that this is Early Access and more will be coming, but so far, I think that only two or three other companions might be added.
So, the choice of companions might not get much better in the full game.
I don't dislike the current companions, but it's not good that most of the companions that will be in the game are already disliked.
And even if they add new companions for every class, there are still a lot of pre-set choices for each of those companions. Once you've played the game a few times you might want to try party compositions that just aren't possible if you only get full control over one character.
Heck, you might want to just try two-manning the game with two perfectly optimized (however you define that) characters. Not possible, unless one of the companions happens to fit your plan exactly. Which seems unlikely.
