This sounds like a combination of a PvP Event and a PvP Tournament.
PvP Event portion - building & submitting the decks
PvP Tournament - actual playing out of the event/tournament
It feels like if it could be fleshed out into a viable tourney it could be a possible improvement over the Rent-A-Deck format.
I think the hardest part of 'developing this idea into a viable tourney' would be figuring out the best way to go about it from an organizational/management standpoint.
Do you
need for players to get their decks within minutes of their actual match? If so it would make more sense to run it as I described above. A PvP Event format for submission and more of a PvP Tournament format for playing.
Would it be just as doable if both players were given their next round decks at the beginning of the round? Then the entire thing could be run as a PvP Event format.
Once all decks are submitted should they be handed out randomly; following certain criteria; or should you get the decks your opponent submitted?
One idea could be to run it as a PvP Tournament and have players PM their decks to the designated host before the tournament starts. Then give each player the opponent's decks to use.
Another idea could be to do a combination of this and Rent-A-Deck where half the decks are created by players and half are created by the organizers ahead of time.
There's a lot of ways to organize this and all will have their pros and cons. It'll be interesting to see which, if any, the organizers decide