I had a look with Team UK to check out Malekith's format, while we would be perfectly fine adapting to the format.
We as a team agreed that the format is very convoluted and has a lot of problems.
1) Outside of the play offs, how would you decide which teams goes first to pick. Would it be based on how the teams preformed last year? whoever ended up losing in the first round? what happens if two teams end up tying? You already have 1 big problem on your hands to make this format work.
2) I would be mostly ok with the format if it was only 4-6 SV OU + Old Gen OUs, However once you start to include lower tiers into the mix specifically UU, RU, NU and PU. These tiers are rapidly changing every month. You can play these tiers 3 months ago, Then you go back to it a few months later and its a completely different tier. Whenever its game freak releasing DLC for that year or a higher up tier like UU lets say for arguments sake; takes Cobalion & Amoonguss from RU to UU.
3) Not having fixed slots will blow hard for the old gen & lower tier players that want to play.
Lets be real here, whenever that you have a good old gen or a lower tier player. Someone will have to sit on the bench and not play depending on the tiers that get picked.
You could have a good UUer, but there can be a scenario where its never optimal for you or your opposing team to pick UU at all. This could happen for every week for the tour.
(Before the tour starts)
"Hey mate, We would be happy to pick you up for UU. we got some good cover for the other lower tiers & old gens so you won't have to worry about playing those tiers"
(The tour ends for your team)
"Sorry mate we couldn't play you at all during the tour, you were never an optimal pick nor the opposing teams picked UU, Thanks for sitting on the bench"
4) To continue from the last point, your UU player can potentially not play the tour from round 1 to all the way to the semi finals. Your team gets to the finals and suddenly the enemy team picks UU. Nobody else plays the tier but the UU Mainer in your team. I find it very silly that this scenario can happen for a Tournament as competitive as WCOP.
5) This format benefits teams who either have a player that can play multiple tiers and having a mainer that plays a low populated tier.
The more mainers and versatile players you have at your disposal, the higher chance your team will succeed. This is also including the fact that you need to make sure you have a solid SV OU line up in the first place.
Lets take Spain as an example who have a really good variety of players who are versatile like Soulwind, Garay Oak and M Dragon.
All they have to do is analysis the enemy team and pick tiers that the enemy is weak in. And just like that Spain have a major advantage against teams that may not be equipped for every tier. You can say Team Antarctica is strong in every tier but RBY OU & SV Doubles. If it turns out the opposing team have a great DOU & RBYer; they will have an major advantage.
6) Finally, if the format does every get approved and we stick to the tiers in Malekith's proposal, every team that plays in the tour would have to account for 16 tiers which is an absurd number. not only making sure your team has 4-6 SV OU players, but trying to make sure you can cover every tier to the best of your team's capability. Some teams will be able to cover all 16 tiers, however for others it can be as low as 9.
No matter what format we end up having, having only fixed tiers is the way to go.