Gavin -
Thanks for a very interesting essay! I was struck by the similarities between your "dimension of constructiveness" and the cosmic intentionality I discuss in The How and The Why of Emergence and Intention. Your allusion to our experience of flow is also, I think, an important clue to the functioning of the universe.
The question of something from nothing is an interesting paradox, one which I explored in the prior FQXi contest (The Hole at the Center of Creation). Nothing is as troublesome a concept as infinity. Even to mention nothing is to imply that it is something (if only the abstract null set - which is, even then, a set).
You stated - "I don't think it is necessary to delve more deeply into what the nature of this state of decision-making would be, as it would be rather speculative to do so." I think this is actually the heart of the matter. Either there is decision-making (intention) or there is not (randomness). We may not be able to observe the difference - but the it makes all the difference in how we perceive the world and how we live in it.
Sincere regards - George Gantz