General Feedback Requested: Microsealed Hybrid Tournament Set on Mirrodin

[MULRAH]

Hey everyone,

I'm hoping I might get some feedback on a one-off format I want to try with my players. I've been putting together a cube for each plane, and we recently tried a Microsealed variant for multiple players. My new idea tries to marry these two approaches for our upcoming run through Mirrodin. I want to capture the flavor of the Mirran-Phyrexian conflict within one or more game sessions, with the player who attains victory for the Mirrans winning the entire cube.

Here are the rules.
Win Conditions

The player wins the cube if he:

1. Wins all three of his matches, and
2. Mirrans outscore the Phyrexians.

The score for each side (Mirran vs. Phyrexian) is determined by the number of decks built for each.
Process

1. The session will begin with 6 preconstructed Phyrexian decks (e.g., BG Infect) comprised only of cards from the Scars of Mirrodin block with the Phyrexian watermark (Phyrexian Score = 6).
2. 4 players start with sealed decks of Mirran cards drawn from a cube constructed from the Mirrodin block and Mirran cards from Scars of Mirrodin block. Players will build 15-card Mirran decks. (Mirran score = 4)
3. Players will now compete to determine the champion who will lead them to victory against the Phyrexians. They will pair off against each other for the first of three best-of-3 rounds. All in-game rules for Microsealed apply.
4. The losers of the initial round will now represent the Phyrexians. Each will select a preconstructed deck and play against each other in the second round. Simultaneously, the winners will compete against each other. They may use their winning deck from the first round or construct a new one (Mirran score = 4-6).
5. The winner of the second round's Mirran matchup is the Mirran Champion and will compete against the one player he has not yet faced, who may select any of the Phyrexian decks. The Mirran Champion may either use his current deck or build a new one from his card pool (Mirran score = 4-7). Meanwhile, the two other players will play preconstructed Phyrexian decks against each other.
6. If the Mirran Champion wins his final matchup and the Mirrans have outscored the Phyrexians, then the Mirran Champion wins the entire cube! Otherwise, the player with the most Phyrexian wins selects one of the Phyrexian decks to keep, removing it from the roster for next time. In that case, there will be one fewer Phyrexian decks for the next session, making it more likely the Mirrans will prevail.

My hope is that these rules allow someone to win the set in the first session, but it will be very difficult. (He would be on the third deck in his sealed pool and would have to beat someone who gets his pick of streamlined preconstructed decks.) By the fourth and likely final session, Mirrans would automatically outscore the Phyrexians, so winner would "only" have to go 3-0.

I realize this format might not be for everyone, but I'm interested to hear if there are any loopholes I'm missing or ways this will become degenerate. I feel like you all have given good format design feedback in the past, and I'm hoping to strike gold again!

- Chris