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Great points. In fact, you have described jynx's utility in such a uniform way that it actually describes vivillon as well since your points really embellish how good sleeper pokemon are. Replace jynx for vivillon in, well, all of your paragraphs and it will still make sense. Change big waters...
The worst thing about jynx is how it can force the opponent into a bad position. If your jynx/ice check is slower than jynx itself at best it is put to sleep. If it is sub jynx it will keep putting you to sleep till it dies and it is behind a sub. If the poke currently out is slower than jynx...
Samurott is a great set up sweeper and kangaskhan is pretty good at wallbreaking. Usually spikers are very important for HO, I've seen them on weather teams as well (garbodor in particular).
Comparing the most recent ban to this potential one, I think there are some very distinct differences (besides the obvious). Combusken / any speed pass was very versatile in the sense that it could pass to anything and arguably make it better. Great checks for this included things like haze...