In the Davis Cup, anyone can compete, from the United States to tiny San Marino. In Test cricket, this is certainly not the case, although there is at least some sort of a pathway, however difficult it may be.
In the Davis Cup, every tie has a context and a purpose. In Test cricket, we are stuck in a meandering throwback to colonial times, where bilateral series are as big as it gets. A World Test Championship has been repeatedly obstructed, postponed, and cancelled.
In the Davis Cup, the crowds are impressive. Packed houses of colour, noise and patriotic support. In Test cricket, attendances are down, tempted away by all manner of things that are more appealing than watching five days of grinding at the SSC, or even two-and-a-bit days of one-sidedness in Bridgetown.
It could be said that everything that the Davis Cup does right, Test cricket does wrong.
The first step is to split teams into divisions of eight. The 'World Group' could contain Australia, Bangladesh, England, India, New Zealand, Pakistan, South Africa and Sri Lanka. There could then be as many divisions as you like below that, but there must be a pathway for even the lowest-ranked teams to work their way up the rungs of the ladder: Great Britain's ascent to the 2015 Davis Cup should serve as a clear enough example as to why that is worthwhile.
Then, the season should be split into three phases. The first could be from January to April; the second could be from May to August, and the third could run from September to November.
In the first phase, a random draw takes place as each division sees four three-Test series played. For example, if Australia
draw Sri Lanka, then they have to arrange a three-Test series during that time period. The team drawn first has first refusal for hosting a home series. If they're not able to do that, then the second team drawn can step into the breach. The random draw is particularly important, because it can facilitate so many more interesting stories than a tournament designed so that Australia, England, India and their best friend play in the semi-finals.
In the second phase, the four 'World Group' winners progress to the semi-finals, which could be arranged again by a random draw.
Everywhere else, the four losers from one division will play series against the four teams who have won from the division below. So, for instance, you could end up with Bangladesh v Afghanistan, Ireland v Sri Lanka, Zimbabwe v New Zealand and England v West Indies. These play-offs are for promotion and relegation between the divisions. If none of the second division teams are good enough to win their play-off series, then nobody is promoted. If all of them are, then they are all promoted.
In the third phase, most of the teams have finished, and will have time to arrange bilateral series to their hearts' content. The only two teams who will still have fixtures will be the two who won the semi-finals. They will then play a three-match final series. This could perhaps consist of a Test at Lord's in September, a Test at Eden Gardens in October, and a Test at the MCG in November. This serves three purposes: firstly, it ensures that the winner will be the best side in all kinds of conditions; secondly, it means that the finals will be played in the world's most famous venues, and thirdly, it should keep the Big Three happy.
The schedule could repeat annually, like the Davis Cup. It still leaves plenty of time for the other tournaments, like a 20-team World Cup. But that, like the Bannerman Cup, is a utopian fantasy.