We definitely need to stick to 2025 to get clear air. There’s a lot happening in other years (olympics, soccer World Cup, rugby World Cup etc).
Keep the 2021 format of 16 teams 4 pools of 4. But to me the best approach is to go with as many double headers as possible at 40,000+ capacity venues. Have something like an Australia/Lebanon/Tonga pool, a New Zealand/Cook Islands pool, a PNG/Samoa pool, a Fiji/England pool. Obviously other teams fill up the other spots and would affect the allocation. But basically:
All 6 Australian pool games in Australia - basically 3 double headers - Lang Park, SFS, Docklands. Match the games to the right cities. You want a Lebanon game at the SFS. In Melbourne, Greece or Italy etc. You want 3 sell outs.
All 6 New Zealand pool games in New Zealand - all double headers
All 3 PNG teams games in PNG as stand alone games
All 3 Fiji team games in Fiji as stand alone games
1 Samoa team stand alone game in Samoa
The two other England games - 1 in Australia and 1 in New Zealand - to market to expats in both countries
The other games as double header undercard games before the bigger Australia, New Zealand, England and Samoa games. Except for say Tonga matches against other island teams.
Double headers will create more of the carnival type atmosphere - you’ve got four nationalities sitting through two games.