With Worlds 2023 "trying" a top-4 Final with repeated decks, I've been thinking about the impacts some more.
Disclaimer: I'm not saying any of the behavior I consider below happened in Worlds 2023. I'm just using the numbers from Worlds as a theoretical example.
As mentioned earlier in the discussion, a downside of re-matching players is that the entire game is different once you've scouted your opponent's deck. Nothing new here. At least players know the potential for that going in, so can decide what kind of surprises they want to include up front or reveal throughout.
The new horror I had was considering the incentive structure for players during the main tournament, which I don't think has been mentioned. It is not unlikely for some of the highest TP players nearing the end of their final game to have very high certainty that they will be in Finals (i.e., if they are going to win their game, or at least not lose by more than 2 TP). In Worlds 2023, for instance, the top players going into the final round had TPs of 21, 20, 20, 18, 16, and then a bunch of 14s. The 20+ players are nearly certain they will be going to finals if they can get at least 3 TP. Particularly for matches with threshold players---in this example a 20 and 18---there is a potential to have an awkward incentive structure. Some examples:
- The 20 player may want to only marginally beat the 18 player to make it more likely that the 18 player gets to a top-4 rather than a 16 or 14 player they previously played and only barely beat.
- Similarly, the 20 player may have played the other 20 player before (as for Worlds 2023) rather than a 16 or 14 player, and it may be that in the 20 vs. 18 game that the 20 player thinks they will do better against the 18 player in Finals compared to the other 20 player they played before.
- The 20 player hasn't played any of the other contenders before, but knows that their knowledge of the 18 players' deck will give them a greater edge in Finals that the other top players who haven't played 18 yet won't have.
In each case, the 20 player who is winning against the 18 player is incentivized to score lower, to be able to "choose" the pool of opponents for Finals.
This is an incentive problem among
players going into top-4 Finals (e.g. final round of Qualifiers)
regardless of whether or not the same deck is used. But requiring the same deck means that not only a player's ability or tendencies are evaluated but certainty about deck vs. deck ability, along with deck surprise knowledge.
The only solution I can think of for removing these kinds of incentives is to not force decks to be the same going into Finals.
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Alternatively, rather than needing to remove those incentives entirely, a related problem is the LACK of incentive among top players with a large enough TP gap over threshold players to actually care about the outcome of their final Qualifier game when top-4 Finals resets scores. E.g., the 20 player above may not care about getting 4 vs. 6 points because it makes no difference for Finals. (To be fair, there is at least more bragging rights for placing higher during Qualifiers, and at Worlds 2023 they even had some physical prizes based on relative placement. But I'm talking about for those prizing the Worlds win.)
For this problem, what if placement in Qualifiers was used as a tiebreaker in Finals or gave some other small advantage, like a starting 0.5 TP separation between Finalists? It
might be possible to make this significant enough to outweigh the above incentives for choosing the Finals pool, at least most of the time, to reduce the concern of players being overly conservative at the end of their last Qualifier game? I don't really like this; I'm just trying to consider different types of ideas.
