I read this and was gob-smacked. I wrote a longer post in response to it but my computer crashed and ate it. And I know you've discussed this already with
@Ovinomancer and so another long response probably contributes nothing to humanity.
Maybe a discussion will be more pleasant than you think.
But I really was gob-smacked. I've never run Dresden Files but I've read the setting-creation stuff in Fate Core which I would assume is fairly siimllar; and I've done a lot of collaborative setting and situation creation using other systems (eg Burning Wheel; Classic Traveller; 4e D&D; Cortex+ Heroic; Cthulhu Dark). I can't fathom how it would take 8 hours, whether or not it was being done by one or four people.
I was probably at least as surprised as you are. I'd participated in some collaborative setting-building in other games, and it had always been part of the first session, and it had worked, and it had been fun. Generally, everyone provided some limited number of ideas and the GM figured out how to incorporate them into something at least more or less consistent.
I'm looking at the Game Creation Worksheet in the Fate Core Book, and it's pretty simple. One page. Two spaces for Issues, six spaces for faces and places, each with at least one issue or aspect, some spaces to note where the game is going to fall on some mechanical spectra, and a little space for stunts and extras.
The equivalent in the Dresden Files game is three pages. One page is the high-level stuff (which we didn't use, IIRC), which has three spaces for themes/threats, each with ideas, aspects, and faces; spaces for the status quo; and spaces for big movers and shakers (maybe we did use this; I'd have to find my notes). The second page has nine spaces for locations; each location has spaces for a name and short descriptions, whether it's connected to a theme or a threat, an idea and an aspect and a face. The third page is like the locations page, but for people, with spaces for each for name, what they're the face of, high concepts and motivations, and relationships. It's a lot more to fill in, and it took us two sessions to get to the point where we were willing to go with what we had. To be fair, there was some broader setting-building stuff before that.
Your remarks that it really felt more front-loaded work than I think it was supposed to and that even with some amount of work, the setting was kinda disjointed give me the impression that you and your group were substituting prep for what the system assumes will be play.
I suspect that, at least for the Dresden Files game, the expectation is that prep (at least setting-building) will be a form or a part of play. Certainly all that work at the beginning seemed like front-loading, and running based on what the players/characters were doing meant a lot more remembering what had come before, and keeping track of what might be happening before the players/characters inserted themselves, seemed like at least as much work as what I'm doing now for D&D, and in some ways more than what I had done for Mutants and Masterminds (the two games I ran closest to running Fate).
As for the setting seeming disjointed, I think maybe that's a matter of it being easier for one mind to be coherent/internally consistent than four minds. Certainly there were some players who wanted things I might not have chosen for a setting, had I been the only one choosing.