How many times have we heard people who don't have the slightest clue how the tiering process works say, this or that Pokémon shouldn't be banned because it'd suck in ubers? Well, our friends at Smogon tried to figure out what things would be like if things DID work that way. And interestingly enough, very few Pokémon that are currently uber would be OU in that case... Deoxys-RS and all Arceus forms except Normal, Ghost and Grass. And... well, I've already expressed my disagreement at counting Arceus' types separately, not to mention, if tiering did work like that, I assume all of Arceus' types would be banned together, much like how some of Rotom's forms were tiered OU in gen 4 despite not getting nearly enough usage to deserve that status. So for all intents and purposes, only Deoxys-RS would be tiered lower than it currently is in such a scenario. Oh, and did I ever mention that I find the way Deoxys-RS was banned to begin with questionable?
On the other hand, several Pokémon that are currently tiered OU would be uber in that kind of system. These are Ferrothorn, Forretress, Tyranitar, Tentacruel, Skarmory, Terrakion, Chansey, Blissey, Scizor, Gliscor, Salamence, Metagross and Heatran. What would a metagame without these, but with Deoxys-RS, be like? Food for thought.