Daisy deterring most players from using the tadpoles was the point, imo. It should be not an easy choice, it should be an evil choice that most would be against, considering the source of the powers. Power corrupts is not a new concept, but if you don't diverge between giving in and resisting the temptation, between the good and evil path, it becomes a moot point.

Whether or not Daisy would have been better, is not possible to say without knowing who they originally meant to be. But at least what was in the EA was more interesting, and not only because the story branched. There were hints that Tav could have been the dark urge, and the dream scenes ended in a conflict between the alien (parasite) and the divine (the taint), fighting for influence over the protagonist. Playing the DU, it seems that even this part of the story form the EA is no longer present.