Astarion: I really don't like him, he care onyl abotu himself.
Gale: Dumb wizard by which mistake and lust for power every one around him can die.
Will: Good who want save people so he borrow power from demon and now don't want pay for it.
ShadowHeart: rude thief, very religious and secretive.
LaE'Zel: She blindly believes in the teachings of her people and trusts her queen. For her, all that matters is strength and the service of the queen.
I don't like any of those companions at all. If you wanted to be friend one of them I will refuse. Ok I can do job with them but I will never drink with them in my private time.
Isn't that the premise though? The party is one of circumstance and less one of choice. There is something rewarding about getting to know a character gradually rather than them just telling you what they are about straight off. I remember romancing Viconia in the previous games, the character showing her vulnerable moments after enough work. With Shadowheart we learn things as to why she is the way she is as you progress,
and once you find out what her mission is and her erased memory comes back or not there could be more
We can also speculate as to the connection they have with the tadpole, being able to pry into eachother's minds could understandably make the characters more distrustful of eachother to an extent.