I am here though I have no opinion on the sleep clause and Dark Void issue (yet), but rather, I would like to talk about the ladder tiers.
First of all, Arceus is banned from normal gameplay as far as I am concerned. For the Uber list, my opinion is to first follow Rory's. I believe there would be many situations like in the singles, such as Garchomp, Shaymin, Deoxys-S, Latios, Latias w/o Dew etc. where it is hard to decide which group they belong to, and these will be suspected for a good amount of time. However, the standard ladder should be balanced, and try to be as open to all Pokemon as possible.
The question comes in: Would the Uber tier be unpopular because of the lack of variations (14 on Rory's list) ? Well, it seems like it on paper, but in the current single battles of Uber already tells us other pokemon is also usable, such as Sizcor, Kingdra, Parasect, etc. and works well together. The problem remains: would non-Uber Pokemon be able to take two powerful hits from an Uber? I am not a fan of Uber ladder, and it would be up to those more experienced players.
On the other hand, the OU list would certainly be different from the singles. Stragegies such as Follow Me, Gravity, and abilities like Inner Focus, Damp, Lightinghod, etc. is limited to certain Pokemon. Since methods can be used with a large number of Pokemon, getting top 25% as the OU list would not be as good as there would be a massive load of BLs. We should be looking at the usage of each Pokemon before making any decisions of this kind.
If the game is overcentralised then that would be another issue, but I reckon it is best to test literally everything possible right at the beginning of the release. The problems then will come up AUTOMATICALLY if there is any.