My more immediate plans, in no particular order:
Continue to clarify the rules. That's really the most important thing to me right up front.
In that vein Powers and Drawbacks should be next.
Powers all rearranged and some editing done, more to do.
Advantages and Disadvantages, which I'm including in Extras, after that.
I should probably divide out the Necronites by Horde and give them their own subpages. Perhaps first into Zealots and Teknicians, then further subdivided.
I'd like to talk a bit more about the Darkworld.
I want to flesh out the Fae (the Aevi). I did not at first realize that's where I was headed, but I often have no clue where I am going in a story until I get somewhere fun and I'm just as surprised as the reader/player but pretend like I knew what I was doing all along.
I need to work up some rules regarding Kindred traits, etc. This will make choosing Kind more meaningful and reflected by things like Kindred Traits such as Regeneration and Weakness to Fire for Trolls and Darkvision and Allergic to Sunlight for Scyldi, for instance.
Further down the road:
Put together character sheets for major NPCs, locations, organizations, etc.
Delve into cyborganics more fully.
Reveal more of the metaplot of the world as it is.
Nail down more details regarding how the whole of modern society in the Super:Natural version of Earth actually works. I hear lots of talk about this bloated movie franchise or that version of "Superman, except he's a jerk", and there are elements of lots of those things that are similar to what I have in mind, but it's all "Yeah, but no."
Probably even further down the road:
After getting everything squared away into the Fate Accelerated system which I will be using at my own table, provide translations for Fate Core for people who prefer a bit more crunch (but really not a lot).