I've always wanted some kind of international 'master league' where you could play through a cycle - four to eight years. Four might be more realistic and straight forward.
- Take 20 teams (test nations plus the current 8 teams with ODI status).
- Up to 35 player squads (as is the current setting) and then load in the best other/upcoming 15-20 players for each nationality; you could have the option to select these yourself while setting up (maybe that would allow an option for using retro players I know that'd be popular with some).
- Players that don't play could have a changing 'form' rating so you could decide if you want to pick them. It'd probably complicate things further, but still would be a nice option, to have these as 'A' players playing actual matches against one another. You could have it that at the beginning of each year you give 35 players central contracts and you can only pick from these players. But come the end of the year you see the record of non-contracted players and you can make changes. Not sure if you'd have retirements and skill changes, maybe, you could have Jimmy Anderson still playing at into his 40s otherwise, although he may do that IRL. Younger players their skills might improve year on year.
You could have a test tournament running over the four years with the end of the cycle culminating in a final match. Maybe a 12 teams round robin or split into two groups of 6. 3 match series (I guess you could have 5 for the Ashes, but I'm thinking in terms of simplicity you would play each team the same number of times).
For non-test teams you could have a similar 3/4-day tournament. This might not run for the full four years, maybe the last 2 or 3. But the aim could be to win that and qualify for a play off against the lowest ranked team from the Test Championship and achieve test status. Of course you wouldn't be able to go on and play test cricket if it's a four-year cycle. Perhaps winning that could 'unlock' the option to replace the side you beat with the one you won with, so that you can play all over again.
Each year could have a limited overs tournament. Obviously you'd want a T20 World Cup and an ODI World Cup and, hopefully have some qualification requirements for them. Maybe these take place in Year 2 and Year 4. So in the years between, you could have the 'Big Ant Cup' and the 'Big Ant Trophy'. Big Ant Cup could be a 4 group of 5 teams T20 tournament and the Big Ant Trophy perhaps a 16-team bracket (FA Cup style) 50 over knockout or top 8 ranked teams like the Champions Trophy or just the same 4 groups of 5 set up, so all 20 teams are involved.
If there are no licenses to determine this sort of thing you could get creative and make it more interesting than a lot of cricket is IRL perhaps with multiple set up options for each format.
I'd love more teams but I think if you took the 20 ODI eligible teams it'd be a good start point; the permanent test members + those with temporary ODI status. You could have an option to switch out the temporary sides with other teams.
If you have perhaps two options for each format when setting up, it'd be pretty cool.
So you could have a 12 team test championship or 2 groups of 6.
You could have an ODI Super League similar to the one IRL, 2 groups of 10 or 2 groups of 7 with a sub group of 6.