It pretty much already happens now as most crap teams play each other more often with zero interest as there is nothing at stake. Perhaps the WTC might change things who knows
No one has said the current system is perfect and more people than not, I would wager, would be of the opinion that every team outside of Afghanistan, Ireland and Zimbabwe who are all very much works in progress for one reason or another, should be playing each other on a reasonably regular basis. The one thing everyone in this thread DOES agree on is that something needs to be done to improve test cricket. Having the same teams play one another all the time with little variety isn’t going to help the strength of the game or the quality of the product.
Now that doesn’t mean I or anyone else wants to see each team playing a 5 test series home and away against every other team, but for every ashes series there should be at least a 2 test series between Australia and Bangladesh, for example.