All this talk of goals reminds me a bit of Sunless Skies.

At the beginning of the game, you declare your goals. It might be Wealth, in which case your win condition is about acquiring a bunch of money, purchasing a fancy house, and collected rare treasure to show off. Or it could be pursuing secret knowledge, and you get a letter from an academic frenemy, which leads down a quest to find out what they learned. You'd travel the same world regardless, but the game knew your specific win condition and could present some story options tailored to what you first chose. And not in generic ways, either, but knowing that you have very specific objectives to meet.

I think that's a problem with the temptations in BG3. They so often offer generic power, or maybe combat abilities. But the combat abilities carry little narrative weight, and they're not strictly necessary for any combat encounters. The Dream Visitor is basically flying blind when trying to figure out what your character needs/wants aside from needing to defeat the main bosses.

Plus, so much of the early narrative is written to assume you want to get rid of the tadpole. And that's it. That's your only goal. It's really hard for the tadpole to tempt characters whose goal is to get rid of the tadpoles, although the Emperor does try it... by arguing it'll help us get rid of them in the long run?

I feel like if the Dead Three or some other faction had been set up as an enemy earlier, then the tadpole powers could be presented as a tempting option to characters whose goal is to defeat this enemy. The tadpole-advocate needs the chance to present itself as the solution to your problems, not the cause of them.