I kind of wanted to bring this up as well. When Kyruem-W and Skymin were banned for good on their respective types, I was a bit overwhelmed by the surprise of that notion, as I could not understand why two really bad types could lose two very valuable assets. At the time, I was still inexperienced enough to not see Grass as a potent threat, and believed that Skymin was invaluable to Grass because it helped eliminate S Rank threats to the type that put in so much work against Grass(assuming that Skymin was scarfed and that the threat was not against an unbalanced matchup, such as Victini on Psychic rather than on Fire). While it is true that Skymin helped deal with threats like Heatran, Yzard, Xzard, Kyruem-B, Volcarona, etc with a respective coverage move or by skillfully flinching it do death, I can now see the cancerous luck factor involved around such a mon and the overwhelming, statistical advantage that it put Grass in against neutral and unbalanced match ups, especially when used with a meme team that consisted of Thunder Wave and/or Stun Spore.
When Kyruem-W got banned for Ice, however, I saw it purely as a buff to birds, and I still believe that to this day. At the end of all of the tl;dr comments, Kyreum-W and Skymin were stated to be banned because that single mon made the type good. That is not the case with Ice. Ice is already a very potent type, and Kyreum-W actually makes it playable in high ladder. Ice has an incredibly unbalanced match up against: bug, fighting, steel, and fire, which all but one are common on the high ladder. Ice also has a bad matchup against: fairy, ghost, ground, psychic, and rock. Ice only has three balanced matchups, one of which is Water, which can easily be an auto lose thanks to Keldeo. Ice only has an unfair advantage against Dragon and Poison.
Now, when we look at the unbalanced match ups, Kyurem-W helps ice against Bug, Steel, Fire, Ground, and Psychic due to Fusion Flare, Ice Beam, Earth Power, and Draco Meteor. However, Kyreum-W fairs no better than Kyruem-B against Fighting, Rock, and Ghost(to a degree). The reason why I feel like Kyreum-W is balanced on Ice is because the type itself is weak to hazards, and Kyreum WILL take that 25% damage every time he switches in because finding the time to spin hazards on Ice is very difficult against unbalanced matchups, which makes him vulnerable to priority. His speed tier also lets him be revenged killed by faster scarfers, as he does not have reliable walls to fall back to unlike other types, especially with hazards on the field, which means that you have to sack some thing every time said scarfer comes in to get Kyreum-W out safely and counter play from there. However, when you cannot eliminate hazards, Ice is always in the short end of the stick of counter playing.
Steel users are probably cringing right now. "But Fusion Flare and Focus Blast spam 6-0s me because Steel literally has the worst defensive core in the tier, unlike Ice." When we look at statistics from January, we find that 68% of Kyreums carried a scarf, while 8% carried specs. 97% did carry Fusion Flare, but only 5% carried Focus Blast. This mean that an Ice user cannot spam either of those moves, as Doublade is immune to Fighting which forces Kyreum out to possibly take future rocks damage, putting it in the Bullet Punch range. Scarfed Fusion Flare only 5HKOs Heatran, while Focus Blast can only 2HKO. A full HP Heatran has an 81% chance to survive a scarfed Earth Power. Heatran can continue to habitually check Kyreum, and will probably end up winning in the long run unless the Ice user is just bad.
It is also important to note that no Ice type learns Fire Punch, Close Combat, or High Jump Kick, and no Ice type outside of Arceus or Castform learns Flamethrower or Fire Blast. This means that when facing Steel types not belonging to mono Steel, you will have to hit them for neutral damage, as things such as Bisharp, Empoleon, Klefki, etc have teammates who either neutralize or eliminate a Ground/ weakness for them. In fact, if you're running Ice and you are NOT running HP Fire, you may as will click X when facing Steel or Grass with Ferrothorn, because he will just meme on the whole team and rack up KOs with Gyro Ball while setting up rocks in the process. Scizor on Bug is no better, as he is bulky enough to eat HP Fires for breakfast and Roost away damage while stacking SDs.
