The broken part about Kyu-B is not that it guarantees at least a kill per match, it's that it takes no skill to do so.
I normally don't mix in with this kind of discussion, mostly because what I say is either ramble or useless, anyway. I'm sorry, but this sentence does not make sense at all. What is the essence of skill exactly? In the end, all we do is choose one of five options every turn and 'hope for the best', does that sound skilful to you? Kyu-B may be overly powerful with it's Attack, and in somewhat lesser extend it's special attack stat, it may be a pokémon that is simply 'choose A to kill B'. With A being 'outrage' and B being half of OU. But is Kyu-B the only one? Far from to be honest. The difference being that Kyu-B does it a little tiny bit different, and honestly not as good... The 'Choose A to kill B' method of Kyu-B only really applies to the CB set, which leaves a lot to be desired: sure it can kill something, but it's slow(er) than most things that can deal with it, locks itself in and can even give the opponent momentum. The Scarf set may make the 'stupidly OP Kyu-B' faster, but honestly makes it even easier to deal with, as tends to be the case with most scarfers, as it lacks the 'Choose A to kill B' that it has with the CB set. Now the Mix-attacker/Sub set, those are sets to watch out for as they can actually come as a suprise to the opponent. But those actually require skill to use, shocking I know.
Back to my statement that Kyu-B is far from the only 'choose A to kill B', he just isn't. A lot of pokémon in Gen5 have gotten the ability to do so, not necessarily 'kill' as much as 'cripple', which in the end is the same, sometimes a kill is even better than a cripple, anyway. Seeing as it gives a free-switch.
Other pokémon that can do the 'do A to x B':
-Breloom: 'use Spore to cripple B'
-Terrakion 'use CC/SE to cripple/kill B'
Keldeo 'use Hydropump in rain to kill B'
'use Hydropump in rain to kill/cripple B'
-Prankster user: 'use status-move to cripple B'
Just some examples from the top of my head, but they are true. (Also, if something doesn't take skill to use, it's rain offense tbh)
Kyu-B has few, useful but few, resistances and fairly common weaknesses. Sure all but one of those types that Kyu-B resists or is weak to are common, but that is what defines Kyu-B. Water and Electric are common in OU, especially with rain, whilst grass is 'common enough' in general. Meanwhile, Kyu-B is weak to Dragon, ROCK, Fighting and Steel. All of whom are common in the OU meta, most importantly being the weakness to SR of course. These weaknesses, along with it's reasonable speed (I refuse to say slow, I mained NU for a while) makes Kyu-B fairly easy to deal with, also don't say something like 'Kyu-B can survive a BP from max Attack Scizor/Breloom/Hurrdurrmurr because Kyu-B will, 9/10 times, lose 25% of it's health once it switches in, and it'll only be less if also factor in it's own LO if it runs it and potential SS damage.
I agree that Kyu-B destroys full stall/passive stall, but honestly it had been insulted, lynched, crussified, kicked in the balls, drowned, hanged, burned at the stake and burried a long time ago already. There's is no reason to bring up that Kyu-B ruins one of the many team-orientations if said orientation was already dead to begin with.
It may sound stupid, but I feel that a lot of people don't even 'prepare' for Kyu-B, the meta does not resolve around Kyu-B because Kyu-B is not worth the effort: it is simply overshadowed by other dragons who bring more to the table other than raw power and not having a 4x weakness against Ice. Honestly I also feel people are using Kyu-B wrong, it just never is the threat it is made up to be, in my experience anyway.
This may sound cheesy but people that claim Kyu-B are doing something wrong in general, something that isn't Kyu-B's fault, but Kyu-B does make it obvious. If you claim Kyu-B is too fast to deal with defensively, then why for godssake are you not running a faster pokémon, the metagame already favors speed so not a lot is 'lost', and if that isn't enough there's always Reuniclus with TR. Want to know what pokémon was really broken back in the day? Salamence in Gen4, that guy was unpredictable due to his versality and not even your steels were safe back then. Kyu-B is such a poor predictable rock that it brings nothing actually new to the table, other than that Skarmory is suddenly not it's biggest wall to take care of anymore.
I've said it before in the few useful posts that I make, but I'll say it again: this Gen 'regular' players have become lazy and resort to the normal things to deal with the normal threats, guess what? Thinking outside of the box, heck just picking an unusual pokémon from UU, can be enough to work out. I just recently started running Prankster Liepard that focuses on crippling opposing pokemon and it does it's job the way it's intended because nobody knows how to deal with it: is Liepard broken? Fuck no. I've ran P2 sometime ago, and when it survived an outrage from a Salamence, my opponent admitted he was suprised that P2 could survive that. Is it weird P2 can survive that? Fuck no. But people simply don't realise something like that anymore, 'the people' are losing 'gamesense' in what works and doesn't, what's good and what's bad, what's actually works and what is just the easy way out.
The difference between Liepard and P2 that I just mentioned, is that Kyu-B is predictable, but people don't know how to deal with it, or don't want to because their super-awesum-special team is already so good that the problem lies with Kyu-B, not themselves. The fact that Kyu-B is so obvious in terms of what it can do, yet so powerful, is honestly not suprising: look at Terrakion or Keldeo. But unlike Terrakion and the MLP, Kyu-B does not have the metagame surround it as much, and as such people don't know how to deal with it.
My apologies for the rambling and nonsense that is within it, but it's normal that I ramble and talk nonsense.