One option is to have two tiers of six Test nations. This appears to be the most favoured option generally, and would likely mean a top division of Australia, England, India, Pakistan, South Africa, and Sri Lanka. There would also be two Associates involved, likely Ireland and Afghanistan. New Zealand could be at the top end of the second tier, replace Sri Lanka when they get promoted, then get flattened by a group of better-funded, better-prepared opponents before promptly being relegated back down again. After all, the only way to improve is to play with someone who's better than you, and the vast majority of Second Tier countries won't get that opportunity.
And the argument that it would benefit Associates is a long way from the mark as well. Even if Afghanistan and Ireland were to be awarded Test status in such a form, then how likely would they be to be playing Tests for very long anyway? Are Bangladesh, New Zealand, West Indies and Zimbabwe really going to bumble about amongst each other playing loss-making Test tours? Of course they aren't. If they want to stay afloat financially, then they'll cut back to the formats that make them money: limited overs.
And there isn't any guarantee that the Associates would even be invited. It's equally possible that two tiers of five would be created. Given that the Full Members have apparently all been given assurances that they will retain Test status, that would leave the Associates out in the wilderness as usual. Or perhaps they'll look for a top-tier of four and a bottom-tier of six. This would well and truly keep the financial four superpowers as cosy bosom-buddies. Australia, England, India and South Africa, all playing each other and netting all of the cash, while the other Full Members desperately try to hang onto their coattails and feed off crumbs. It would be like nothing had changed.
The reason this is even a discussion is because the ICC have finally realised that the four-team World Test Championship is a feeble idea at best. It is a format that would alienate most of the cricket playing world, lack purpose for all but the top few nations, and essentially be something that with the proper scheduling of tours, would be the preserve of the financial top-four. But what made all of that a problem was that it meant that the world's broadcasters wouldn't care a jot about it.
So yes, scrap the WTC in its present form. It's lousy anyway. Replace it with something bigger, something along the lines of a festival of the greatest format of the game. Twelve teams, four groups, fifteen Tests, five weeks. A gruelling schedule perhaps, but one which allows the broadcasters to pick out the fixtures of most interest to them, or to buy all of them and hand the choice over to the consumer. It would be a huge tournament, would give the Associates some actual meaningful opportunities, and could be the catalyst for the inclusion of new Full Members.
Scrap this tiering rubbish, though. Don't even let it get on the table. It will not end well for anyone, and that's just the brief synopsis as to why.