I completely agree with your theory, arby, and I have based myself off this assumption to this day for my quest through Lucid Dreaming.

Thinking about it, lucidity must come (assuming a DILD) from non-lucidity, that is the situation where all the processes and thoughts are going about at an unconscious level, like the knowledge of the fact you're dreaming, or the development of the dream scape and dream themes. If some of it was conscious, by definition one would know it is a dream, thus (s)he would be lucid. So, if anything would make us lucid, it must come from unconscious thoughts and processes, like habits, or beliefs.

The same thing can be said for WILDs, since conscious thoughts keep the mind and body awake, and thus there is the need for something more subtle.

In fact, I came to the conclusion that awareness would be one of the main roads to lucidity. Awareness means being more conscious of what's going on around you, and of course, what's going on in the dream is the dream itself, thus you would more easily recognize it as such.