Companions are so much a matter of taste that I’m not sure she could take anyone’s word for it. Plus we only have part of the game and don’t know all the companions yet, though are expecting Minsc and Jaheira from BG1 & 2 to be able to join us later in the campaign. But even in early access, I think lots of folk have found characters either amongst companions or NPCs that they’ve really enjoyed. Others, of course, have been disappointed.
Personally I’ve found something to interest and engage me in all the companions so far, though with some reservations and whether they work in the end will only be shown when we get the full game.
The interactions are far more in depth than BG2 and certainly than BG1 where companions had very little dialogue at all (though many had a lot of impact despite that!). It may be more like Divinity 2 for all I know, but I’ve never played it so I guess I’d say the interactions are more like Dragon Age than BG, but to me that’s a natural evolution. I’m reasonably confident that I’m going to be content with the companions and interactions in the final game, and it’s still possible that I’ll be more than content if they live up to their full potential.
As to whether folk we meet are a-holes, I think it’s fair to say many of the individuals we meet are flawed in various ways. But then I think the same is true of BG1&2 and I’m not sure they’re any worse. So, in short, I think she may need to read or watch some reviews and clips when the game is out and make her own mind up whether she wants to give it a go.