The top four in each division seems generous. I was assuming that each division champ would get in and then the next two with the best record, regardless of division. But the top four can work, as well. There is enough chaos in BB that I can see the case for more playoff teams. But the more playoff teams we have, the more I see the case for an entire Swiss Draw season and make the entire season the playoffs, instead.
I don't know. I'm not sure. But I think I like the Bracket 2 option because it fosters more cross division play. The Bracket 1 option can be interesting if the divisions are not random. If, for example, you put all the new teams in one division and the returning teams in another. Or if you put the bashy teams together and the agile teams in their own division for the finalists to face each other out of their element. But I guess that same principle can work for the Bracket 2 option, as well, just to more effect.
After consideration, I think I like the idea of deciding divisions rather than randomizing them. I mean that's what the NFL does - they target regions and traditional rivalries and encourage those rivalry matches to drum up fan support. It's artificial, but it seems a better narrative than random. And if you're going down the narrative path, have it make some kind of sense where the "good" teams play each other and then compete in the playoffs against the "bad" teams. Or bashy and agile stay separate until the playoffs. Or new versus returning. In that scenario, I think your Bracket 2 idea makes the most sense as you prepare for the regular season much differently that you would prepare for the playoffs. It has more of an NHL feel to it, where you can be the best, undefeated, passing team out there only to get matched up against the lowest seed Nurgle team in the other division and have your ass handed to you because you were not building a team during the regular season to confront Foul Appearance and Disturbing Presence. I kind of like the idea of having one path to winning the division and another entirely different path to winning the playoffs.
Anyway, just my two drachma.