First, yes, I know, Greninja will be killed by anything that hits it, but if I didn't include it there would be that one idiot that would pm me that I missed it, so I decided to include it for the sake of accuracy.>Greninja
U mad bruh?
One, adding Greninja kind of made your post look stupid.
Second, Kyurem-White isn't going to switch in to anything Zekrom is using but scarf Bolt Strike, and if it you do try to switch in to Kyurem-White, you can only really switch in on Fusion Flare. Kyurem-White also has 95 speed and STAB Ice Beam/Draco Meteor. You'll lose unless you're Scarf and they are Spec.
With that said, I do agree that it is a good mon. However, B-Strike + Outrage/Dragon Claw coverage means that if its banded or scarf, a Pokemon can easily sponge a hit and go to a mon that resists the move. (P-don, Xerneas, etc) Orb is kind of too slow for practical use, and the lack of power is noticeable. And this Pokemon relies a lot in prediction skills, and a Pokemon relying on only prediction skills to be effective is going to lose you games in the long run. Of course, it feels satisfying when you win via prediction, but I doubt it will get you too far, as it also means that the opponent can beat you if they predict better than you. And if your opponent is using a Xerneas, you will be blocked from using Dragon Claw, as even if you kill a mon with Dragon Claw/Outrage, you become total set up bait to Xerneas afterwards. This mon is too high risk, medium reward for my liking, at least.
TrumpWobbuffet for president.
I think it would be fine if this thing got promoted to B+, but not A or A-.
Second, I fail to see where I had once mentioned anything about Kyu-W switching into Zekrom or vice versa. I realise I did talk on the Shuca Berry, but I specifically mentioned a neutral Ice Beam, as in one not affected by STAB. Furthermore, I fail to see how your analysis of a Kyu-W vs Zekrom battle actually makes sense, as you do mention both of them starting on a 95 base speed, which already puts the win chance at 50/50, far from hopeless. Then, taking into account that near all Kyu-W are Choice Specs, the Specs/Scarf matchup isn't overly unlikely. Even if Zekrom has a poor chance at beating Kyu-W, which I honestly do not believe, your argument here has little relevance to Zekrom's overall usefullness, as Kyu-W is only one Pokemon.
I can appreciate your arguments on the Choice items, and it is entirely possible for an opponent to switch into Pdon or Xerneas to avoid Zekrom's STABs. However, your argument voids itself here on the basis that your team has six Pokemon as well, and pre-emptivly switching is just as easy for you as your opponent, and as such neither momentum nor pressure is lost, meaning that this argument is barely viable and not a good enough reason, at least in my eyes, to prevent a promotion.
I do not see how your arguments on prediction add any particular merit to your overall case either. Zekrom, although capable of taking the field for an extended amount of time, is primarily intended as a revenge killer, not a sweeper. Due to this, large amount of prediction are not required at all to use Zekrom, as KO'ing a weakened Pokemon is not difficult.
So far, the only argument you have presented worth considering is your point on Xerneas. However, a check such as Xerneas, which is easily devistated by moves such as Bolt Strike, is no good reason for Zekrom to not be promoted, since even the best of the best, the S-ranks, each have checks and counters.
I apologize if I seem cold, but I spent too much time on my speech to be shot down this easily.