Since it's been really bothering me, I'd like to post a few thoughts about the event card this round:
first off, I hadn't really noticed that instead of having to decide the card sacrifices blindly the decision had to be made during the first day of duels instead, which brings me to the most important part two:
never, ever allow teams to make any deckbuilding choices after duels have already started like has happened this round. I don't think it became a very big deal this round, but you can significantly modify your deck with upgrades. That is to say: increase your chances of winning by basing your decision off of duels that have happened so far, discouraging duels during the first day. This is horrible imo. Please avoid anything that allows decks to be altered during the duel phase. I'm not talking sideboard-like stuff of course, but for example we could've had a quanta-low fractix with unupgraded Phoenixes vs Darkness general, notice they haven't used pestal anywhere during other duels in the first 23 hours and 59 minutes and THEN decide to upgrade the Phoenixes causing the deck to swim in quanta.
This is but one potential case of exploit in allowing such changes during duel phase, so please avoid them in the future, thanks. I would have warned wms about this earlier, but like I mentioned: I did not even realize these decisions had to take place during the duel phase until it had already started. So waiting until the first day had passed hoping no one would abuse this seemed like the best option.