My own view is that this radical incompleteness of natural science with respect to consciousness entails, at the minimum, an equally radical agnosticism about the ontology of minds and persons. It means that we are not in a position to insist that materialism is true, and that therefore nonmaterialistic hypotheses and research programmes cannot be rejected a priori. The appeal of a dual aspect theory is that it avoids the difficulties of ontological dualism, but it is indeed mostly hand waving. It does not really explain why it should be that the stuff of the world has irreducibly distinct categories of properties. As I see it, dual aspect theory is largely an attempt to disguise the incompleteness of materialism.
Ontological agnosticism is more candid.
This line of thinking has some interesting corollaries. Zombies are, in relation to us, in the same predicament that most of us are in relation to those mystics who report back to us their experiences of what is sometimes called superconsciousness. We can ape what they say, if we want to, but we don't really know what we are talking about. There is a literature on the question as to whether the things that mystics say count as evidence for the reality of a transcendent order of some sort. Given the absence of an independent way to verify their statements this presents grave difficulties.