What are you on right now
Get sober and come on back.
“Oh it’s got bulk and it can sweep shit might as well warrant a rise!”
I had no idea these were good points to make when debating someone. I get it, my thoughts are unpopular. I get it, people want to disagree. That's fine. But, I appreciate it if people actually put up points. If people did not just say what a mon does on a shallow level like saying what moves it has or its stats & leaving it at that. Instead actually talk about its worth & debate the points that were made. I am not in it for the likes, agreements, or anything like that. I'm only here to discuss points. If you prove me wrong, I don't mind. You agree with me, fine. Just try to be civil about it.
"S Rank will be the top of the top, incredibly dominant Pokemon who don’t really have any equal."
Hydreigon does not fit under this category. Its moreover a great anti-meta mon. Its not dominant at such a high degree due to the facts that it simply always has to keep up with the meta and adapt. The meta is never adapting to it.
Hydreigon runs scarf to keep up with fighting spam, fast threats (Mega Mane, Zeraoara, Mega Beedrill, Mega Aerodactyl, & Mega Sharpedo), and Latias (S rank threat).
Hydreigon runs a myriad of sets in order to not get walled so easily. Choice Specs, Flash Cannon + Life Orb, Z-Belch, Super Power + Life Orb, and Steelium Z + Flash Cannon + Super Power. It runs them for Blissey, Popular Defensive Fairy Cores, and Steel Types (Fire Blast on almost every set due to the massive amount of Steel Types).
Now, Blissey is not run solely for Hydreigon, its ran for special attackers period. Same goes fairies & steels (for other respective reasons). So no, Hydreigon is not centralizing them around itself.
If it runs specs, it sacrifices speed and has a bit of 4MSS in what it wants to run (Fire Blast or Flash Cannon). Z-Belch is similar but it also sacrifices power and puts itself in 50/50s since you can only use the move once. Life Orb sets (including Steelium Z) only have one drawback in speed but, it still means a lot considering how fast this meta is & how many popular mons have priority.
If it runs Scarf, it loses to fairies and can be choice locked into the wrong move a lot due to the heavy amount of mons that either resist or straight up immune to its STABs respectively. Normally forcing to go for U-Turns. Scarf is easily the best set as the item allows Hydreigon to stand a better chance against the high speed tier meta. Being able to out speed Terrakion, Latias, Mega Beedrill, Mega Pidgeot, Mega Aerodactyl, Zeraoara, Mega Sceptile, Cobalion, Celebi, Azelf, Moltres, and Tornadus. All of which can KO it. That's a long list.
All of this proves it is not dominant to such a high ranking degree. Now for the equal part.
Z-Sets - Latias does this better due to better bulk/typing, better speed tier, and being able to simply run psyshock for Blissey. Dragonium Z, Psychium Z, and Electrium Z are all terrifying sets that make Latias a threat in it's own right. At the same time, Latias can still use Draco Meteor, Psyshock, and Thunder/Thunderbolt before or after using the z crystal. Scizor is another mon that is better at using z moves with Fightinium Z + Super Power. Terrakion is the best at using z moves to be honest.
+4 252 Atk Terrakion Continental Crush (180 BP) vs. 252 HP / 240+ Def Eviolite Gligar: 411-484 (123 - 144.9%) -- guaranteed OHKO
(Gligar is not a counter as EQ 2HKOs. So, if you switch-in, that's one SD. You EQ, that's another SD. BOOM. Gone.)
Life Orb Sets - Scizor is much better at this due to priority BP, allowing it to handle faster threats. Same goes Mamoswine & Bisharp.
Choice Scarf - Latias, Infernape, and Terrakion are better. Latias can tank hits better while still firing off high power moves and out speeding almost all mons. Infernape has a stronger U-Turn and can run gunk shot for fairies while being to deal good damage against much of the meta with it's strong STAB moves. Terrakion has better STABs, more power, and higher speed.
Jack of all trades - Mega Altaria is better. It can go special or physical. Better at roosting due to typing. It can run DD for sweeping. Better defogger due to typing. It's also harder to predict due to it's amazing movepool, bulk, power, and being able to go physical or special. And can fit on any playstyle. Hydreigon has trouble fitting on stall. The only thing Hydreigon has over Mega Altaria is being able to run choice scarf to fix speed issues. At the same time, if you decide to switch-up sets with Mega Altaria you don't really have to worry about taking away anything. Mega Altaria always does big damage due to pixilate. It always has bulk due to its amazing typing and stats. You're never really sacrificing that much unlike with Hydreigon.
There ya go. Hydreigon is the best at nothing.
It's hard to fit on teams due to it's many weaknesses defensively: Fairy, Dragon, Fighting, Bug, and Ice. So, you have to run a Primarina, Scizor, Latias, Infernape, Terrakion, and Mamoswine switch-in(s).
Mind you, I made the S rank noms for Primarina and Mega Altaria as they don't have these same issues. Primarina is the best choice specs user, easy to fit on teams (due to bulk, typing, and power), and it's tough running a defensive Primarina check on teams though you should always carry one. Mega Altaria is the best at being Jack-of-all trades, many mons runs moves just for it, easy to fit on teams (due to customization in stats + moveslots, bulk, power, and typing). Almost forgot Terrakion. I could see disagreements on this due to its typing not being good with defensive synergy. But, it is the best physical attacker in the tier (see the calc above with gligar).
I don't mind if people want to argue these points but, try to be civil. These points are valid. Try to respect the work I put in this post, as well as the other posts I made. Thank you for hearing me out.