Clearly I've done a poor job of explaining my position and I wanted to clarify my zygarde experience since your brought it up even though arguments should stand on their own merits. I have built 4-5 serious teams in the last two months including the two RMTs in my signature (which were chosen because I think they're interesting not because they're my best), all of which have peaked in the 1850~1950 range. One of those teams had glare zygarde on it, the others all had multiple natural checks without me even gameplanning for zygarde. For the record, only one was a stall team as that's not my natural playstyle and I've been doing a lengthy tour of styles as preperation for making a great balance team. Choose to listen to or disregard my opinion based on my credentials if you want.Forget the fact that your explanations above on various supposed countermeasures are questionably and the fact that you spam Unaware Clefable + Acid Armor Reuniclus stall on the ladder. If all you boil Zygarde down to alone is simply the offensive variants being able to break through and the Glare set being able to cheese through, then you're missing the point of the suspect test and perhaps Zygarde's effectiveness in itself. I'm not saying Zygarde is broken, but between three Z moves, 2 boosting moves, 2 status moves, the ability to run Rest or Substitute, and a plethora of viable spreads, Zygarde has ways to circumvent a lot of Pokemon on your list that you simply credit far too much. You have to consider things in a broader sense here.
It is entirely true that Zygarde can only run one set and you can oftentimes deduce it from team composition or gameflow, but that does not mean that it has some "4mss" or is "limited" more than other things so much as it has ways to adapt to counterplay. I really think that you and a lot of others should stop trying to look at things in such a linear fashion and instead read the OP and consider things in the context of actual games. Posting a list of checks/counters is generally a linear way of thinking. Instead, try to consider all of the options and play a bit more with it. Pokemon is a games where checks and counters exist, but it's also a game where things are more complicated than just simple checking and countering when other elements come into play such as progressive chip, status, hazards, team support, set uncertainties, etc. Yes, Zygarde is stoppable in the confines of the current metagame and I am not entirely sure it is broken given how stoppable it is. I do not know what I am voting, but I know I that if I am going to vote DNB, it will not be because of anything remotely along the lines of your list of checks/counters or your bizarre limitations of one of the metagame's most versatile Pokemon.
I have great respect for Zygarde's versatility and ability to weaken teams for its team mates, or hax through its counters in a pinch. My point with the lengthy checks + counters list is that Zygarde DOES NOT constrain team building, like at all. When I build a team there are certain mons I make sure I have an answer for, zygarde does not make that list because I can randomly assemble 6 mons from the VR and have a good chance of having 2-3 answers to it. Now don't get me wrong Zygarde is good and I agreed with the nom to send it to S-tier. It contributes to winning games, it just doesn't win every game.
Your "broader sense" seems to be hinting at zygarde's unparalleled versatility as its broken-ness. Philosophically, I don't see how versatility alone is a threat. Maybe its because I play ladder and not tour, but unpredictability to me is part of what makes this game fun. You want a complete information game with no hax, play chess not mons. I consider zygarde's versatility a good thing, I've played entire games assuming a mon (not jsut zygarde anything that viably runs multiple sets) was one set only to discover in horror at the end of the game it was something completely different. I just don't see why this is a threat to the meta. I have the reqs to vote and will be voting no unless I see a really convincing argument why its broken, but what I've seen so far seems to be mostly sour grapes about parahax mixed with it can beat this specific counter if it runs XYZ set.