A topic that's came up in the past and never had an official resolution is how Arceus should be treated in DPP Ubers. This 10+ year old debate still makes an appearance in Ubers often enough that I'm making this thread to provide options, discuss with the community, and then make an official tiering decision call on how to handle Arceus.
Small disclaimer: Finding information on the history of all this is tricky and mostly second hand, so take any past info with a grain of salt.
Arceus wasn't obtainable in-game until its events released it at level 100 during Platinum. It was available through glitches, but there were no legal means to bring it to a battle. As it was only legally obtainable at that time as an event lv 100 Pokemon, it couldn't be EV trained beyond 100 EVs in a single stat through the use of vitamins - this was known as "Farceus". Back when Shoddy was the simulator, Arceus was never coded in despite its release due to technical difficulties - the EV limit couldn't be programmed in. This meant that Arceus was technically banned, but never given a proper chance or reason. Time moved on and the community came to accept* this technical ban as normal as DPP ended and grew old, and its stayed that way to the present day.
* This was a contested debate even before Arceus's official release. Many arguments used here no longer apply to what we know today.
A couple of years ago a glitch was discovered that allowed you to both capture Arceus and escape the area, theoretically allowing battle with it. As it can be caught at lv 80, it can be EV trained as normal - I will refer to this edition as "Fullceus". If leveled to 100, it can even be transferred to modern games, so it is effectively cartridge legal. This was all figured out in the previous thread on the topic, and is a highly suggested read to those wishing to discuss things here as I will be using arguments brought up there.
With the background cleared up let's bring this to topic. Arceus is banned without due process, and this thread aims to give it exactly that. As Ubers operates on the standard of allowing as many Pokemon as competitively possible (otherwise expressed as minimizing bans), I believe that Arceus should be looked at as a new Pokemon to the DPP Ubers metagame and given a tiering decision from that perspective. That means the following choices:
1) Arceus is enabled and unrestricted. (Fullceus)
2) Arceus is enabled and restricted. (Farceus)
3) Arceus is officially banned for being too strong in DPP Ubers, rather than for being unavailable.
The reasoning behind an unrestricted Arceus makes it my preferred choice. For all intents and purposes, Fullceus is legal. Even though obtaining it can be considered a glitch, Smogon is only avoidant of mechanical glitches, rather than those that affect Pokemon availability. Back in Diamond and Pearl, Darkrai and Shaymin were only obtainable through a similar void/tweaking glitch that Arceus is available through now, yet they were enabled on Shoddy before their events. Glitches are generally banned if detrimental to competitive play, which this doesn't fall under. While these Pokemon were not playable on WiFi, we simulated based on local battles, where these Pokemon could be played with.
NOTE: Event move Arceus (any set with Shadow Force, Spacial Rend, or Roar of Time) would still have its Farceus restrictions.
Farceus is a secondary method to allowing Arceus that I believe is a poor choice of action for reasons covered earlier, but is mentioned as a possibility for the glitch avoidant among us. It would take a significant community consensus for this to be the course of action, and I think should only be considered as a complex ban aimed to balance Arceus in the metagame rather than elected for as a policy decision against glitched Pokemon.
Officially banning Arceus is the flip side of things. From early discussions with players, there are those that either feel that Arceus is simply too strong to allow in DPP Ubers (especially in its unrestricted form), or feel that the metagame should be untouched and banning Arceus is the means to that end. To those that feel this way - you should post your reasoning. Making the official call to ban Arceus is possible given the unique circumstances surrounding it, but it should be justified properly.
To bring this topic to a conclusion, 1 will be considered the primary choice and will be chosen if discussion is either inconclusive or has low community participation. The default choice for Ubers should be to keep Pokemon wherever possible and those that feel Arceus is "too much" for DPP should argue as such rather than appeal to an arguably false tradition such as metagame age. Smogon has changed past metagames on bigger discoveries than this.
That being said, there will be an understandable perspective that rocking the boat is undesired or unnecessary, however, this loophole has been left open to debate for over 10 years. If you have a horse in this race, you should give your opinion. I don't aim to enforce a choice that is widely unpopular and have no strong opinion either way - I'm trying to give the playerbase room to decide with a justified default choice to break any locks. I mainly want this to have an official resolution before DPP Ubers features in the 2020 tournament circuit and in our upcoming team tournament in <2 weeks. Thank you for reading!
edit: If you have an informed opinion on this and don't have PR access, you can send me your thoughts in a forum conversation and I can proxy post on your behalf.