Thank you tjdaas for bringing this thread to my attention. I strongly agree with what shrang has to say and want to add my own points and perspective.

My understanding was that the reason OU had the initial banlist that it had was because of some notion of having OU feeling like the upper end of the in-game power level.* I think as the generations have advanced OU's been getting further away from this notion. My opinion of what OU should be (in terms of initial bans) is that it should be tier with the fewest bans required to achieve some desired level of balance. I'm not sure whether it's something similar to this or similar to the first notion which is meant to define OU currently on Smogon, but, if that's what OU is, there is no reason whatsoever to assume any bans at all. I would definitely suggest that having an expedited banning process at the beginning of a generation or major release (think ORAS) is a good move in that scenario, though. For what it's worth, this or something similar has been my stance for a while, but it's always been a fairly fringe position (to start off without any bans at all). However, I'm aware of and would note that there was a vote by senior staff just before the beginning of the 6th generation on whether the initial banlist should be nothing, or should be something of a holdover from the BW banlist - the latter was voted for near-unanimously, with only Great Sage and Jellicent dissenting.

For what it's worth, regarding the ORAS 1U thing (that being ORAS Ubers with a couple of bans like Geomancy, which shrang mentioned) and so on, I think balance is really a matter of degrees. I can't say whether ORAS 1U is more or less balanced than ORAS OU because I never played ORAS OU seriously, but I would note that there were fewer viable options in ORAS 1U - though at the same time, it isn't that far out of step with some of the lower tiers of the generation. ORAS Ubers has somewhat fewer viable Pokemon than ORAS 1U did, and it's certainly more centralised (in fact, I would describe ORAS 1U as fairly uncentralised); I'm not sure that it's less balanced, though. I think ORAS Ubers is better balanced than people give it credit for, though. Outside of centralisation, it's not that easy to argue to ban Primal Groundon.

By the way, for my own personal tastes, I don't think Latias (without Soul Dew, of course) would be unbalanced in ADV OU, but we don't touch historic metagames any more - even though, originally, Celebi and Jirachi weren't in OU until the owner of Netbattle decided they wanted to include them in OU (yeah that arbitary decision should be allowed to stand but we can't make a far more thought through and community-oriented change, mhm?).** That being said, even if you change an old gen OU (like freeing Latias in DPP - right decision), keep the old version of OU playable still and so on, history matters!

*Echoing what shrang said, "OU is forever trapped in a mentality that has a defined power level that they are unwilling to move out of", my understanding from talking with people like (if I recall correctly, Aldaron) is that this is the case. I know some people like M Dragon just think that ubers isn't balanced and no tier with fewer mons than OU is balanced enough either, but if it's not the case that everyone thinks like M Dragon does about it, then either make things explicit or make changes. If what tennisace says, [Quote]This is mildly off topic but there's decently clear line that TPCI/Game Freak has between "mons designed to be broken af" and "shit you can use". The restricted battle competitions provide a pretty decent (yet very imperfect line) between the two. Of course, we know things like Kyurem-B aren't as OP as they were supposed to be, and we don't think that event-only Pokemon such as Mew should be banned. However by and large, the line rests at the "cover legendary" level.[/Quote]is the actual standard, then make it the standard.

**Shouts to Lilyhollow (formerly Kristoph, and formerly permitted to post in Policy Review), who I was discussing much of this with and said that they remembered that a lot of people were very mad at the time that Celebi and Jirachi were freed.