This is an interesting article from the Japanese media, which says that Japan is interested in joining the UEFA Nations League to prepare for the 2026 World Cup.
https://www.msn.com/ja-jp/sports/soccer ... cb2040ae6b
However, I can't see how this would be possible in terms of the schedule. The 2024/25 UNL is expected to be played in September, October, and November 2024, which coincide with the Asia WCQ 3rd round which Japan should participate in.
But I do expect Japan (and a few other Asian teams) joining in 2026/27.
As for 2024/25, I also expect UEFA will invite guest teams, since this has been discussed in the media for a while. They can add the South American teams and/or the 3 North American World Cup hosts.
Even if South America keeps the 18-match qualifying format, they can possibly still squeeze the UNL in if they start qualifying early. They can play 8 matches in September, October, November 2023 and March 2024 (I expect Copa America in June 2024), and the other 10 matches in 2025.
Also, the cynical side in me thinks that the last time a big team (Germany) was relegated, UEFA expanded League A to rescue them. And this time, another big team (England) was relegated, so....
Maybe the teams can be distributed like this.
Total: 67 teams (54 European teams + 10 South American teams + 3 North American teams; I am excluding Russia for now)
League A: 28 teams (16 teams originally to be in League A + 4 teams originally to be relegated to League B + 5 South American teams + 3 North American teams)
4 groups of 7 teams, single round-robin (6 matches)
The schedule of each window can be something like this:
Window 1:
Wed: 1 v 2
Thu: 3 v 4
Fri: 5 v 6
Sat: 7 v 1
Sun: 2 v 3
Mon: 4 v 5
Tue: 6 v 7
Window 2:
Wed: 1 v 3
Thu: 5 v 7
Fri: 2 v 4
Sat: 6 v 1
Sun: 3 v 5
Mon: 7 v 2
Tue: 4 v 6
Window 3:
Wed: 1 v 4
Sat: 7 v 3, 6 v 2, 5 v 1
Tue: 4 v 7, 3 v 6, 2 v 5
South American teams would obviously play their home matches in Europe. North American teams could possible play at home if the matches are on the East Coast (Mexico likely want to play in the US given their fanbase). The only League A team which is too far away from North America is Israel, so we can restrict them drawn in the same group.
League B: 20 teams (12 teams originally to be in League B + 3 teams originally to be relegated to League C + 5 South American teams)
5 groups of 4 teams, double round-robin (6 matches)
League C: 12 teams (12 teams originally to be in League C)
3 groups of 4 teams, double round-robin (6 matches)
League D: 7 teams (7 teams originally to be in League D)
2 groups of 3 or 4 teams, double round-robin (4 or 6 matches)
There will be promotion/relegation play-offs between the leagues to balance them correctly (or perhaps not even necessary if new teams are added for 2026/27).
And for European League A teams, finishing in the top two means you are eligible for World Cup play-offs (this prevents too many dead rubbers in the final rounds), together with the group winners of other leagues.