I honestly think the tadpole powers are cool, but I never go down that road. Like others, I've only ever done that path like once, maybe twice. I mean, as you see your companions deteriorating and becoming obviously more messed with by the tadpole's strange transformations, it becomes less and less of a temptation.
If they REALLY want to make the tadpole a valid part of the game, they REALLY need to step up the temptation aspect of it.
I remember my first playthrough. I spent so much time on my Dream Lover in the beginning. Then I got to the end, expecting to meet her as I sailed off the shore in the Underdark, only to not find her ever. I went out and looked up what the deal was with her, and I was stunned to discover she was only accessible if I gave in to the tadpole.
What? Why would I do that? Anything "Illithid Powers" related is only obviously going to turn me into a Mind Flayer that much faster. So why on Earth would I ever use them? I had no reason to.
So all that time on the dream person was wasted because I was thinking, "I'm NEVER going to give in to the tadpole. EVER.
All that work they did for the Illithid powers you get, and I've never even tried all of them. I think the druid is still the main one I haven't done. Why? Because there is nothing I like about the illithid tadpole path. Nothing makes me want to go there because everything about it is totally negative except the tadpole powers, and even those you can't use very often.
That's all I'm saying here. Why waste time on all that if you aren't going to at least make it more tantalizing for the players. Give us reasons to actually go down the path to the Dark Side.
And make the first Dream Lover sequence happen somewhat early in the game, maybe even before Raphael, and grant us those powers right away. THEN I'd be more tempted.
Imagine. Shadowheart's down to 3 HP. The spider matriarch, I know, is about to come for her. She has that Survival Instinct ability. If she falls, she instantly gains HP instead. Oh yeah! I'd be tempted to have her use that power because it's right there, teasing me. "You know, if she falls, you have no more cleric - no healer. It'll make the battle so much harder."
Or, the gith fight. Astarion uses his dark cloud power to bound in and out of darkness, constantly gaining advantage and sneak attack on the gith, and they have disadvantage against him. The battle's going poorly, and I know that power could turn the tide. Should I use it?
If nothing else, giving the powers for free right away would certainly make going down the tadpole path more appealing, especially if you didn't realize that when you use the powers, it brings you closer to the tadpole.
All this, "Do you use the tadpole to pry into her brain" thing is not very tempting.
