I've already listed possible checks for it on flying.
The only check on flying is Mega Gyarados, nothing else switches in on ice beam. What you listed are revenge killers, please note the distinction as it makes a very big difference. I'd like to put a replay here, where in my opinion I outplayed my opponent, who I know quite well and found it relatively easy to work out what his next move would be, but still couldn't do anything about the Kyu-W despite building my team specifically to be able to beat it. If I counter-teamed a pokemon and outpredicted the opponent on a number of occasions, yet still couldn't beat the pokemon, something's wrong.
http://replay.pokemonshowdown.com/monotype-165166563
Ground: Sand Rush Exca, Quagsire, Swampert, Scarfchomp
Electric: thundurus-I can cripple it, scarfed electivire (relying on speedtie but oh well), Protect Magnezone with SpD Investment to see if it's using earthpower or fusion flare, then make your move there,
Poison: Scarfed Drap, Scarfed Gengar, Sashed Nidoqueen, Tentacruel for ice beam, dragon pulse and fusion flare hits, You could test out assault vest Dragalge(however you spell it)
Dragon: Scarfmence, Scarfchomp, Scarfed Hydreigon, Sash Drud, Scarfed Latios (all these aren't uncommon)
Steel: Scizor the bane of ice types, Hazards Alone on steel teams cripple ice teams, Scarfed Jirachi isn't rare on steel, klefki for screens or to cripple with t-wave, Metagross with bullet punch could do decent damage, then revenge with someone else
As for ground: Exca's a check, though it's OHKO'd by fusion flare and can be OHKO'd by earth power. Moreover, with ice beam doing 70% there's no way it'll win unless sand's up, which is something of a large requirement given abomasnow will be fighting the weather. Quag and Swampert are 2HKO'd by ice beam and can't do anything in return, and Scarfchomp obviously dies on the way in although it revenges. The obvious one you missed was Gastrodon, which hard walls it. However, Gastrodon also hard walls Kyogre so the fact it hard walls Kyu-W doesn't stop it from being broken. Moving on.
Electric: Thundurus-I can para, but it can't switch in on ice beam (obviously) and is OHKO'd after paralysing, meaning that you have to sack something, bring in thundy, sack it while para-ing,
then revenge kill. That's two pokes sacrificed just to give you a chance of beating this monster, and assuming it stays in to get paralysed in any case. Electivire is 2HKO'd by ice beam and OHKO'd by draco, while Cross Chop doesn't OHKO back. It can't even win 1v1 even if it wins the speed tie.
Poison: I used to run poison stall, and I enjoyed using it. Then Kyu-W and Skymin came along. I haven't used it for a month which is a real shame. But moving on:
Tentacruel kinda beats this... in terms of being 3HKO'd (assuming no Stealth Rock or prior damage of any form, which is hard to avoid given it being the rapid spinner and having no recovery) and it can Knock off back, making it much easier to deal with in future. That said, it's barely a counter. It still dies if it comes in on Kyu-W. It's like saying Sableye counters MMaw: Sure it can burn, but then it's still OHKO'd by play nuke. Anyway, Amoonguss (that great pokemon capable of beating both standard Xern and RestTalk Kyogre) is 2HKO'd by ice beam even running max SpD ass vest, and the only other thing not completely shredded by earth power is crobat which... let's just say it doesn't particularly like ice beam. Or draco meteor. Or fusion flare. Or a stiff breeze for that matter. Once again however, you listed a number of revenge killers, some of which are quite imaginative (I mean running sash on nidoqueen just so it can revenge? Being forced to revenge is bad enough, but running sash to do it as well?) And ass vest dragalg - no. Just no. It
can live two ice beams, if it's extremely lucky, only for draco meteor to do a max. 80% and then it dies next turn. Grats on your pokes created for the single purpose of beating kyu-w which doesn't even succeed... Trust me, I enjoyed playing poison. It was fun. But while this monster is around, poison is dead. It struggled to compete in a metagame filled with psychic and steel as it was, but now there's no way it's competitively viable. This pokemon which makes one type supposedly better (though teams now are forced to build around a single poke) completely annihilates another type. It didn't work.
Moving on.
Dragon: Sure, they revenge kill. TBH I'm not gonna argue on this one, if you've ever seen a dragon vs. dragon game you'll know that's all they ever do. Just a small note would be that if you do happen to run a bulkier Kyu-W set, scarf latios' draco has only a 50% chance to OHKO, meaning it could take 2 pokemon out before your opponent can deal with it, due to not knowing what it's running. It does give Kyu-W an edge, given its versatility. And also, please don't mention sashes as counters because while revenge killing is all well and good when it comes to dragons, sashes aren't exactly the best for revenge killing. If your revenge killer for Kyu-W is sash drud and your opponent sets SR (which it's all too easy to do), gg.
Steel: Now here's the funny thing. It was decided that ice should be buffed when it came up in conversation that +2 Mega Scizor simply destroys ice. The funny bit? Ice now has an absolute monster available to it, and yet
it still dies to +2 Mega Scizor. Between easy hazards, decent revenge killers and the occasional annoyance like skarm stopping fusion flare and forcing Kyu-W to switch, steel easily beats ice like it's always done. And moreover, it's simple enough to get Mega Scizor to +2 Whether or not Kyu-W exists. Sure, a good ice player can beat a bad steel player now that Kyu-W's there, but at a high level of play the steel player will still beat the ice player whoever's better.
Anyway, that's enough ranting from me for now. I've been planning to make a post for a few weeks, but my last draft got accidentally deleted so it may be a few days yet. But expect a decent-length post with a number of never-before-seen arguments, which will blow your mind and get Kyu-W banned. Hopefully.