Since the start of the World Test Championship around 3 years ago, the format introduced by ICC has been in question, whether the format is the best one or not to determine the Test Champions.
After many years of trial and error the World Test Championship was finally launched in 2019. The final of the 1st edition of WTC was played in June 2021 between New Zealand and India in which New Zealand became the 1st Test Champions in the history of test cricket after defeating India by 8 wickets.

The format purposed by ICC for the first couple of editions has 9 teams out of the 12 test playing teams taking part in it with Zimbabwe, Ireland and Afghanistan not being part of it. Each teams plays 3 away and 3 home series and the top two teams according to the points table at the end of the two year cycle plays the final for the Mace.
The 3 away and 3 home series are bilateral in nature and only the final is organized by the ICC, here the matches in a series are up to the boards to decide whether it will be a 2,3,4 or 5 match series. In the current format the boards are deciding the number of matches and the teams against whom they play. This creates an imbalance between matches played by different teams and against whom which team plays in the Championship and also all the test playing nations are not able to participate in it. This has been the major criticism of the current World Test Championship model.
How ICC Test Championship can be Improved?
Still it has been a great initiative taken by the ICC to have a Championship for test cricket. But it to be more efficient a new model has to be introduced sooner or later.
Having a league system for the Championship can be the answer to having a model similar to the ODI World Cup. The league system will also help many test playing nations to make money of test cricket as many countries lose money in hosting test cricket.
The league structure will have all the 12 test playing nations participating in the tournament over 4 years to determine the Test Champions.
This league tournament would be organized by the ICC in which the top 8 teams according to the ranking will automatically qualify for the tournament and the bottom 4 teams would take part in the qualifiers. Two top teams from the qualifier tournament would join the rest 8 teams.
Then the 10-team tournament that would be played over the period of four years will have 2 groups of 5 teams, which will be formed according to the ICC rankings or their position in the previous edition of the World Test Championship.
Each team in a group will be playing 3 matches in a series, two away series and two home series with the teams in their groups. This would mean having 12 matches per team in 4 years, that will be 3 matches per team in a year.
Other than the 3 matches per year in the WTC tournament the cricketing boards can keep organizing bilateral test series as it was done in the past. This way the boards can also keep making money from bilateral series.
Every year there will be one series which will be organized by the ICC and teams can play around 3 bilateral series per year according to the desire of their boards. This would mean 4 series per year for a team compared to 3 which is played in the current WTC.
Organizing a 3 match test series in a year for each team is something that will not have a huge financial burden on the ICC. And if it does then may be the ICC and the cricketing boards can split up the cost.
At the end of 4 year cycle the top 2 teams from each group according to the points table will go on to play the semifinals and the winner of semifinals will play the final. The window required for the semi finals and finals will be around a month so that will have to be managed by the all the boards and the ICC.
This new type of World Test Championship tournament will help smaller test playing nations to have at least some form of test cricket. Also, every team will get same number of matches in the tournament. In this way test cricket will have bilateral series and a World event which will help WTC and test cricket to have more significance.