Hi there OGC, nice to hear from you.
I'm sorry I can't agree the translation of 'tov' as functional. The author fails to match her words with sufficient examples and, anyway, one of the principle lexicons of Hebrew, Brown Driver, Briggs (BDB) doesn't agree either. It suggests good or pleasing, which, in the context of the Genesis passages, seems about right. To try and attach other meanings to the word is, frankly, pushing it a bit and trying to bend the meaning of the text. Even the best modern translation, such as the new Jewish Tannach, stick with 'good' and for good reason. Sure, 'functional' digs one out of a hole as regards theology, but that's no excuse for going against the meaning of the word. So I go with the majority, and my BDB, and stick with 'good' here.
Now we could argue a bit about what that might mean but as god is often defined as good I think we would end up having to accept that if god though something good, then it actually was good.
Of course, this is viewing the text as though it were history and someone was sitting next to god making notes as it went along. Clearly this is not the case and the source of the text is not the original things that happened to form the world. The story appears to me a modified version of the Babylonian account of creation in which the Chaos Monster has to be defeated before any meaning world building can begin. Our Genesis account reduces this to the chaotic nature of the earth. Nonetheless, what we have is some priests' conception of creation told after the Babylonian tradition and is, in effect, an attempt to create monotheism from a story that was polytheistic. They did a great job.
I agree with you regarding myth though - a story to convey more meaning than the words and that could be easily explained is something like I would go with, Myths have been important in all civilisations but the key part is how much people get from the myth and not how much people believe the myth is actually true history. It is easier to manage not to fall into that trap if there are dragons and so on instead of creation of course.