Well, yeah, I have to agree that I don't think Joss had a plan for the First plan. The first was amorphous in every way, which was why it was such an ineffective villain. The best villains have a passion for something, a desire for something, and in the best of all worlds, they think that they are just in their crusade.

But, for the sake of world building for the context of a story, I'm trying to think of what a First inspired world might be.