I wanted to converse with the mindflayer while it was in a disadvantageous position - it's intelligent and it doesn't want to die, and it has a story to tell and knows things, important things. That's a huge part of what social interaction in games like this is all about, but Larian's writers never even entertained it as a possible option that players might want to pursue.
Or perhaps the Mind Flayer is not particularly interested in conversing with what it views as slaves and livestock. Offer your brain to help it survive, or kill it. There's no other options because the MIND FLAYER is not interested in anything else.
Larian writes conversations like fights to be won, or expressions of dominance, and nothing else. The idea of having a conversation where someone isn't actively trying to boss everyone else around, or lord their superiority (in some fashion) over the other person, seems to be an almost wholly alien concept to their scripting so far, and that, more than anything else, is going to make the game distasteful and a struggle to enjoy. It was what made DOS2 unenjoyable as well. Maybe the intro and the scenes along the beach and nearby areas where you're gathering your party aren't actually going to be indicative of how conversations go for the rest of the game... but if not they are a terrible, terrible way to start out and introduce players to them.
What you're describing does not fit my recollection of my multiple playthroughs to completion AT ALL. There are numerous conversations where you can simply ask questions and get to know more. The only adversarial conversations tends to be ones where tensions are already high. There are options that are less "assert dominance" and more "deescalate the situation," though. They're skill checks for the skill Persuasion. If you're trying to Intimidate, of course it's going to be like you describe.
