Offering power by dangling the dream person as a reward? Reward for what? That doesn’t make any sense.
But if your character isn’t interested or doesn’t trust the dream seducer then denying them is an option, so what’s the problem?
I was referring to your suggestion about gaining the power from the dreams rather than a dialogue choice, may have misunderstood this. If there was another entity involved, the dream person would be extra incentive to get you to go the power route, so in a sense, they would be a reward. Kind of like how crime lords get the nice cars and the hot girls. Having this done by a separate entity would also allow for more headcanon of what the dream person means to you.
I think this is a problem of pacing of the first Act, narratively you're supposed to feel an urgent need to go forward, but meta-narratively you understand there is no real threat and want to see more content. so Larian is in effect writing a story they assume their players will disregard for gamey reasons, which is why we have so much tied to long rest-cutscenes and the tadpole dreams. I don't think they should assume players will rest after every combat, I think that because that's how I played on my first run, putting off a long rest for as long as possible, I never saw the tadpole dreams either for that reason.
Another reason I wish there would be a day/night cycle, would make it a lot easier to figure out when to rest. Or at least make it known sooner that we don't have to rush, although I still think any sane person would want the tadpole gone as fast as possible, unless we are given a good reason to keep it.