16 teams is good for the next tournament. People are looking forward to seeing who will be the other 2 teams, assuming all the current 14 teams qualify. And there's plenty of countries chasing those spots for the first time. Serbia will be going for another shot once again, Canada could be good leading into the 2025 world cup, Jamaica, Malta, Greece, Belgium, Holland, Spain etc. Then there's Russia and South Africa trying to make a return to the World Cup.
We had 16 teams in 2000 but 15 were already named without any qualifying matches and very little internationals leading into the tournament.
This will be way different.
There's no reason why it can't work. We already put the lowest ranked team into Pool A with Australia. The super pools have worked okay in the last two tournaments but that should be the end of it. Like I said before teams 4-13 can go from challenging the big 3 to beating each other by 50 depending on a few players. Scotland were ranked 4th after last year but now they are weaker than most of the teams in C & D.
More importantly it gets rid of the win-one-game-and-qualify nature of the super pools. PNG and Ireland both look great but one of them will miss out on the finals (and auto qualification for 2021) to Lebanon who only had to beat one team to get in. Similarly in 2013 all three teams in Pool C were better than any team in Pool D, yet USA got through thanks to the organisers stacking the pools in favour of Wales.
I see no reason why pools along the lines of
A - Australia, Samoa, Scotland, Italy
B - New Zealand, Fiji, Ireland, Cook Islands
C - England, Papua New Guinea, Wales, USA
D - Tonga, Lebanon, France, Canada
couldn't work. 11 of those teams have been in 'super pools' before, and all but Canada have faced the big 3 before.