1800 seconds = 30 minutes. 300 seconds = 5 minutes. If we take the game duration up to 131 (15 in-game days, calculated maximum time), 5*15=75+30=105 minutes. If we multiply by four, we get 420 minutes or 7 hours. 7 hours per game is more than enough. You can play it in one go (maximum two). That’s firstly.
Secondly, gathering four players at the same time is not an easy task, and doing it several times is almost impossible.
Thirdly, waiting for your turn will take three times longer than playing 1 on 1.
Fourthly, increasing the time per turn drastically increases the game length and consequently can significantly prolong the tournament. I don't like playing in a rush myself, but in this tournament, there's no other way. I hope you understand.
For the same reason, the WT version was chosen. Starting armies, battle time, and fast battles. Don't worry; by default, the settings will be MAXIMALLY ADJUSTED FOR SoD
For those who don't know what WT is, you can read the list of differences HERE