So I have been reading through the comments on whether there should be an initial ban list of pokemon in OU or whether the tyrants of Ubers like Arceus and Kyogre should be allowed to play with the likes of Terrakion and Politoed. Truthfully speaking, the goal is to create the best metagame (balanced with multiple viable play-styles at one's disposal). The current OU metagame has been lacking in diversity for quite some time where players are complaining about too much weather is being used and only HO or balanced offense teams are viable and stall is dead. I would go as far as to say it is a fact that if there is no initial ban list, and pokemon deemed broken would then be suspected and possibly banned is the best way of achieving a desirable metagame. If we start off with an initial ban list, the question of "I wonder if this would actually help solve some problems the current metagame is having" would be asked about them. This process would take quite some time, but it would result in a metagame that everyone would enjoy.
I feel like players have also, for the lack there of a better word, been brainwashed into thinking that cover pokemon deserve an auto-ban. Shuckle Man has mentioned Giratina-O along the lines of possibly deserving an attempt at the OU metagame. At first thought, I thought it was ridiculous. After looking at it's stats, i have quickly grown to the idea that maybe it would be suitable in an OU environment because of it's low base 90 speed and ability to only hold it's signature item, the Grisceous Orb. It's too late to test it out in the BW2 metagame, but we can see how it performs in Gen VI along with other mons deemed broken this gen.
For the people claiming that if we had no ban list, than the OU of today would be the UU of tomorrow and so forth, that is not exactly true. Yes, some pokemon would suffer from the new additions to the tiers, but that happens every generation that comes in. Pokemon changes tiers based on what is brought upon each generation, whether it be new pokemon, moves, or abilities and if how they get altered. Some things in the lower tiers may see an increase in usage, for example, Swift Swimmers like Ludicolo, Kabutops, and Kingdra. Some pokemon would also simply stay in the same tiers as before.
If there was a very minor ban list made up of Arceus, Kyogre, Groudon, and Mewtwo to begin gen 6 though, I do not think a lot of people would complain. It's simply banning mons that have obvious hinders to itself that would make people they can be suitable in an OU metagame is what we would be avoiding until we realized that these mons or either broken or not, and I personally think that we should have at least a chance to have a hands on experience with it.