Aha, I had laid it as an "Evolutionary Trait" as an easy way of identifying with it, both for myself and for others due to my tendency to base even the mystical as if it were a form of science. I tend toward metaphorical comparisons when describing things. That it was for easy identification was the reason I left "evolutionary" in quotes, as it wasn't literally a form of evolution as per Darwin's "survival of the fittest" definition. 

That in mind, I agree with your interpretation for the most part. However, you must remember that Ouramancy is [i]not[/i] a trait gained solely from families' interaction/experiences with gods, but also as a consequence of experiences with the infernal and things less than gods but more than mere mystical beings.

If the trait were solely a gift from the gods to speak with them, it would carry the implication that divine spirits are always benign, to actively be giving gifts that allow humans to communicate (that is, to transmit and receive emotions and informations) with not only themselves, but all supreme magical beings in order to better deal with things like demons plaguing a family. 

However, it would make absolute sense that this may have been the initial intention and purpose of Ouramancy, that a god or the gods had gifted it to humans so that they could have messengers. The gift in turn somehow began to function as a sort of mechanism where it could automatically give itself to families based on their experiences with supreme magical beings of all levels and inclinations, bringing me back to the ideology that it's a "passively emitted mutagen", so to speak.

It should also be remembered that one doesn't just become an Ouramancer, but instead, their children, grandchildren, etc. do. This is almost perfectly in-line with the thought of it as an "evolutionary" trait, rather than just an instantaneous gift.

[b]tl;dr[/b] Originates from the god's more or less good intentions, but now something that comes from any meddling by higher beings.