I agree that dialogs could be improved and that maybe it would be good if there are a little less "tadpole-centric". I mean, reading the forums it seems I lost a lost of conversations for choosing to never use the tadpole powers. In part because it seems that using the tadpole make it stronger (narrative wise) and partly because you can choose to respect others provacy even if you don't trust them yet. And apparently, that means that many scenes at camp won't trigger, but don't offer alternative.
Well, I think that choosing to not use the tadpole should have alternative dialogs at camp and also a counterpart:
1. If the companions become aware that you choose to not use the tadpole powers, that should get some kind of reaction. Some like Astarion would think you are stupid for not doing it. But others like shadowheart might appreciate that you respect their privacy.
2. Since companios have tadpoles, some of them might want to use the power on you. And you should be able to notice when the fail to do so. And be offered several reactions. That would be nice.
Then there is the part of custom character vs origin character. The example of a mage talking to Gale is an example of how conversation options might need a little more work. I mean, when Gale says your magik is weak, you should be able to prove him wrong and get back at him latter. Also, while it is part of the romance, why Gale can access the weave but a wizard character can't?
Right now, it seems most conversation choices are geared towards showing you "how cool are the origin characters". Well, Ok, but maybe as the story progresses the custom characters should be offered choices to "get even". So if Gale is condescending to a wizard character, maybe latter you should be able to tell him that you already knew that or that "in fact" he is wrong and correct him. Or, you know, speak as colleges who respect each other and doesn't look at the ither as "lesser". The problem is not that companions are arrogant or evil or whatever, that is ok. The problem is that there are not reactions that allow the player to say that you think they are those things or to tell them to "tone it down". Or even to respect your privacy and that you don't want to tell them your past. I mean, why do they get to not trust you, but you are forced to trust them and answer? That should be a choice.
I get that you can't have infinite choices, but you can have a few that aren't variations of the same (Trust the companion or not talk at all).
As for reactions, I agree that some times intent should be the thing judged, regardless of success. And once the relationship starts to improve, it would be nice for companions to show interest by asking you things and by trying to earn your approval. That would create a sensation of reciprocity... In a way, Astarion is the only one who I have seen to do that when he agrees to only drink from enemies (or animals, even if that make him angry).
But I don't think dialogs are bad, just limited and with unreliable triggers that many times mean that you miss on them.