The future of international cricket will be shaped this week at the most significant ICC annual conference in recent times, as 150 delegates from the 105 full, associate and affiliate member nations descend on the Caledonian Astoria hotel in Edinburgh for six days of talks. There are five big-ticket items on a packed agenda:

1. The revamped world Test championship

A proposal is on the table for the creation of a two-division Test league system – seven teams in the top tier, five in the bottom – that is hoped would add greater context to the current bilateral tours by feeding into a points system beyond the current rankings. Played over two or possibly four years, from 2019 onwards, and with a Lord’s final also mooted, it would see two new Test teams added with promotion and relegation between the two divisions, as well as the ICC Intercontinental Cup (the first-class competition for associate nations that sits beneath Test level). Test series could still be scheduled outside of mandatory league fixtures, making established high-profile encounters such the Ashes still possible should England and Australia, for example, be in different divisions.

2. Greater relevance for ODI cricket

As well as looking at the future of Test cricket, there is desire at the ICC to raise the profile of bilateral 50-over internationals outside of World Cup years beyond 2019. Plans are less developed than for the five-day game but one known to have been floated is the creation of a 13-team international league. Under this proposed system, teams would play a three-match series, either home or away, against all opponents over the course of three years – 36 games in total – with the top two sides playing off for a title decider at the end and the bottom-ranked team possibly relegated to the ICC World Cricket League (the second tier of international teams). The league would be a possible boon to associate sides such as Ireland and Afghanistan, as it would offer the fixtures against bigger nations they currently crave and allow other associate upward movement from the WCL.

3. Additional World Twenty20 tournaments

The 2016 World Twenty20 in India was far from perfect at ground level but its commercial success – and the challenge of domestic Twenty20 leagues – has prompted a rethink over an original plan to move the tournament to a four-year cycle. The next edition was slated for Australia in 2020 but tournaments could now be staged in 2018 and 2022, with the 50-over ICC Champions Trophy possibly phased out after the 2017 tournament in England as a result of the shortest form’s marquee event remaining biennial. This move, along with revamps for Test and one-day cricket, would require a rethink of the future tours programme – it runs up until 2019 currently – and would need to be rubberstamped by the ICC board.

4. International playing regulations

Following a meeting of the ICC cricket committee at Lord’s at the start of the month, a number of proposals have been put forward to the ICC chief executives’ meeting on Tuesday and Wednesday. As well as urging greater consideration of how best to implement day-night Test cricket, the committee has recommended the ICC take greater control of the decision review system. Included in this is a recommendation that umpire calls on lbw reviews are relaxed – with 25% of the ball needed to be hitting the stumps down from 50% at present – and that incorrectly called no-balls be reversed by the third umpire. There is a desire to make helmets that meet the British Safety Standard mandatory across the international game and that suspect bowling actions be monitored more closely at domestic level.

5. The Big Three model

The ICC chairman, Shashank Manohar, was elected in May with an apparent mandate to review the so-called “Big Three” structure of the governing body that was introduced in 2014 and saw India, Australia and England take a leading role in running the global game, as well as a greater proportion of the revenues from global events. Steps have already been taken to remove their permanent seats on the ICC executive committee but now a further debate will follow regarding the overall model and distribution of funds. Manohar, who previously described the structure as “bullying”, stood down from his position as president of the Board of Control for Cricket in India when taking his current, and now independent, post. His replacement, Anurag Thakur, has been non-committal on any changes, however, and they would require approval by the full ICC council that meets on Thursday.