Despite your inconclusive logic, I'll attempt to respond to some of your points.
So far i cant find many differences between the suspect and the standard ladder. On both ladders you fight the same teams just that on the suspect ladder you dont see Deo-D Offense anymore. So we kinda just wiped an entire playstyle out for no apparent reason.
That is because Deoxys-D is only used on HO teams with a spinblocker. Since Deoxys-D is testbanned for the suspect, then obviously you're just going to run into your standard Sand Balance and Rain Offense you found in the other ladder.
Deo-D was never a problem so far for me neither on the Ladder or in tournament matches (i.e. OST#9). Deo-D doesnt sweep you, it doesnt set you up to 100% win because hazards can be prevented or spun later and it needs support to protect those hazards. Deo-D is good and probably the best offensive Spiker but its not broken.
I've always found Deoxys-D somewhat troublesome in both the ladder and in tournament matches. What do you use to counter it? As of late I've been using Forretress, but even then I am often scared to lead it versus Deoxys-D since if it has Hidden Power Fire I lose a Pokemon and it gets hazards still. I even have used Xatu to an extent; however, many players have reverted to using Skill Swap which makes them get hazards! "Scouting" Deoxys-D isn't as easy as it is for offensive Pokemon because if you attempt to "scout" and it doesn't have the move that could kill your counter, it just gets up free hazards. On good Deoxys-D teams you don't have much time to spin. The team is based on offensive synergy and if you're against a competent player you will not have time to spin most of the time. E.g. they sack they have Choice Scarf / Focus Sash Gengar to OHKO Starmie + Tentacruel with Shadow Ball and Destiny Bond respectively. Obviously Deoxys-D isn't broken because of its offensive sweeping abilities, but because of its supporting abilities. That is such a redundant point. Read
here as to why I explained Deoxys-D is broken despite the support it often requires.
I am often able to prevent Deo-D from getting 2-3 Layers + SR up - usually it just gets SR and maybe 1 Layer Spikes. Amother point that proves that Deo-D isnt broken is the fact that i can still win even if Deo-D gets full hazards down. 3 Layers of Spikes + SR =/= auto-win, it just makes things easier and if you use the time Deo-D uses to setup Hazards effectiviely you can probably sweep or at least kill some member of the opposing team.
The common average is usually Stealth Rock + Spikes. I am rather surprised that you still win against Stealth Rock + 3 layers of Spikes; however. I would like to see some logs of this. Typically if you get so many hazards down, the opponent is going to be at such a disadvantaged state that they have almost no shot at winning. As I said earlier:
I have seen people in this thread scoff at the idea of Spikes making Deoxys-D broken, and I am astounded at how Spikes are underestimated. Assume that a team has 4 Pokemon weak to Spikes and all 6 neutral to Stealth Rock. Now assume that Deoxys-D sets up Stealth Rock + one layer of Spikes, something that typically happens in most matches. Although this is obvious Theorymon, I just want people to see the damage of the support Deoxys-D provides. If Stealth Rock + 1 layer of Spikes is in play with the afforementioned Stealth Rock and Spikes-weak Pokemon on your team, that is 125% damage if each Pokemon just switches in once. In more stall-based games, that number could double or even triple. If you're weak to Stealth Rock then the number will obviously go up as well. Keep in mind that 24% can be added if you set another layer of Spikes. In perspective, that is a little over 1/5 of your team's overall HP lost from just one layer of Spikes and Stealth Rock. Deoxys-D sets these hazards exceptionally well without any counters.
If you have Thund-T or Volc out vs Deo-D, Deo-D cant safely lay Hazards down for example because it risks you setting up. Therefore it has to Taunt/Twave/whatever and cant do its primary job (providing Hazards). And you all are talking about how LO max SpA Thunder Deo-D beats Starmie/Tentacruel. So what, i ask? If i lead with SubVolcarona and your Deo-D decides to TWave i get an immediate advantage. Every Mon can run something to prevent certain Counters to beat em. If your Terrakion gets often killed by Scizor you can run Babiri Berry and if you want to kill Gliscor LO-HP[Ice] does a good job at that. You can mold every Mon in something that has a chance to beat its counters but this approach isnt feasible for this discussion. Why? Because these 'niche'-sets are practically worthless if your opponent doesnt use these particular Mons but other means to stop Deo-D.
First of all, you assume Deoxys-D is going to always lead. If your Deoxys-D "lead" is as obvious as Volcarona or Thundurus-T then I could easily lead with a Terrakion and you will be automatically at a disadvantaged gamestate. Thundurus-T, if the Modest version, is slower and I can easily Taunt as you boost. The same applies to Substitute Volcarona, even if it is faster. The common Red Card version makes Volcarona cringe since I get a free Stealth Rock while you lose your Substitute after you attack (assuming turn 1 Taunt) and I could possibly get Spikes as well. Volcarona isn't going to want to not Substitute either since I could possibly have Thunder Wave as well. Terrakion with Hidden Power Ice is gimmicky and weak and we all know this. If it holds Babiri Berry you are easily revenge-killed by common Scarfers and you're still easily OHKO'd by common attackers that are faster. Deoxys-D cannot be OHKO'd by almost anything, which is why it is so deadly. If these "niche" sets are worthless versus your team, you still are unsure what moves it actually has. It has so many possible options that you can't really do much against it without being fearful of getting Hazards set up on you.
BTW in SPL or OST#9 i have seen people use Deo-D rarely. Maybe that is an indicator that it isnt broken if even not the majority of the Tournament-Battlers is using it.
Usage doesn't indicate whether a Pokemon is broken or not really.