I would really vote for a simple system which gives at least theoretically a chance to finish the tournament withing 6 months.
Thus I definitely prefer SINGLE ELEMINIATION and - please don’t hate me for that - just one game per round.
I also vote for normal bids then - this would at least reduce the raffle effect as e.g. Axis lovers don’t need to play Allies by chance and “just” need to offer very high bids to get their beloved side.
I still like the idea to simultaneously play 2 games with switched sides, however I don’t know what to do in a 1-1 situation. I think a 3rd game would definitely take too long and I am not sure how a tie breaker could be found to make a rather quick third game.
I just learned from the previous playoff brackets that even 8 players single elimination took more than half a year.
And please keep in mind: the league takes a year and everybody is totally fine to accept the league champion who also “just” played 3 single elimination playoff games.
A single A&A game takes very long already, I simply think that this (imo) disadvantage should not be enhanced by a complex and probably bloated tournament system.
my 2 cents.