Ok, this is getting absurd. Look, I get it, Naganadel is good. It has good coverage with Draco/Sludge Wave/Fire Blast. It has very good Special Attack and Speed. But this idea that it's getting a guaranteed ban is overhyping it, plain and simple.
One of my Smogon/Discord buddies has a server where they programmed in the SM mons/move tutors for use in Custom Game. We had some simulation USUM matches using Naganadel, among other things. What we found is that Nasty Plot Dragonium is one of the most overhyped things in existance. Sure, Poison/Dragon is a good defensive type, possessing only 4 weaknesses. Thing is, all of those weakness (Ice, Ground, Psychic and Dragon) are all common types used by common Pokemon. And with 73/73/73 defenses, it's not like you're going to be soaking up hits like a champion. Nasty Plot Dragonium Naganadel is like every other frail SDer/Nasty Plotter in existance: It can be extremely dangerous if you let it set up, but it'll cave to just about any form of offensive pressure. Remember, Nasty Plot sets will often be unable to make room for U-turn, making it harder for Naganadel to pivot and wear down checks, especially considering how weak U-turn from this thing is (as someone showed earlier, you need to run 80+ attack EVs just to have a chance to KO Hoopa-Unbound with it). And unlike something like Deoxys-Attack, you don't have so much immediate power that you can slap on a Life Orb and sweep without even one boost. You're right, garbage like AV Tyranitar will eventually die out. This is because the Naganadel hype will wither out with it, and people will find checks and counters that are better than freaking AV Tyranitar.
I'm not saying Naganadel will be bad, no, I'm not saying that at all. Hell, I could totally see it in A or A+. But this idea that "OMG so broken it's gonna get suspecteded and banned!!" is just silly. Naganadel is broken? I'll believe it when I see it.