Tournament rules for "One for All".

from the organizers' point of view, 3 is preferable – the tournament is better structured.
from the players' point of view, 4 is better – the inevitable skill difference is leveled out by the brackets, and more people can participate.

but at the same time, in the playoffs, it could be played like in the Davis Cup – 5 matches, but in a different order – pairs within their own brackets, and 2 vs. 2, which is played if necessary.

pros: 2 vs. 2 with random castles – this hasn't really been done before (by the way, there's nothing wrong with random castles; you just need to approach restarts differently).
one replay instead of 4 games.

cons: some of the captains may not be fans of 2 vs. 2, but this will become clear when discussing the proposal, and it is quite possible to take this into account when picking players.

and in general – the tournament is a team event, and 2 vs. 2 is the embodiment of team play, and I think it would be more fun.