By Smogon's tiering definitions we would ban snover under the
Support Characteristic
A Pokémon is uber if, in common battle conditions, it can consistently set up a situation in which it makes it substantially easier for other pokemon to sweep.
Snover makes Walrein fufill the Defensive characteristic, and pushes Froslass into something somewhere in between Defensive and Support as it was on the fence for BL on Support even without hail and now it can very viably run defensive sets.
Offensive Characteristic
A Pokémon is uber if, in common battle conditions, it is capable of sweeping through a significant portion of teams in the metagame with little effort.
Defensive Characteristic
A Pokémon is uber if, in common battle conditions, it is able to wall and stall out a significant portion of the metagame.
Having said that I believe Frosslass and Snover to both BL independent of each other by Smogon's definitions.
@MM87
This responds to your statement. Wheather it ended up being inferred in the final definitions is something one of the policy makers will have to let us know.
I don't see how Walrein is broken by any means under hail, which is what you just proposed. I haven't seen any post in this thread about Walrein being broken with hail, as there are many ways to combat it. Taunt and Encore being the immediate solutions.
I don't have much experience with UU, and I am looking at this argument from a Philosophical stand point, and considering the arguments and evidence provided in this thread.
Your argument is that Snover is broken because it makes it
substantially easier for Walrien to wall a significant portion of the metagame, and for Frosslass to basically just fulfill every portion of the characteristics. However, I'm going to argue that this assumption is very wrong, and ill-thought out.
First, as I mentioned, Walrein is in no way suspect because of his hail-stalling at this point in time. I haven't seen anyone else complain about his abilities to sit there as you take hail damage, so it's a non-question to me. However,
with support from Frosslass I can see how he could be broken. A set like, Protect, Sub, Super Fang, Roar, is potentially very harming with support from Frosslass, because of the spikes that one could potentially have on the field. Also, if their spinner is dead, you now have a very potent threat in Walrein to stall and roar, if you play the cards right / get lucky. However, this is not evidence for the banning of Walrein, but the banning of Frosslass, as she is making it easier for Walrein to wall, and cause a lot of damage with Hail and spikes, and potentially Stealth Rocks, floating around, and not an argument for the banning of Snover. Snover sets up a situation where Walrein can stall, but does not set up a situation where he can do a lot of damage with little countering options as opposed to having no Spike support. Hail alone doesn't make Walrein potentially BL, and in my opinion, even with spikes, he is still easy to counter.
Now, as has been argued, it seems that in Hail, Frosslass is certainly broken, or at least that is the general consensus. If she was close to BL without hail, it is hard to imagine her not being even closer, if not actually, BL with hail. But, who is to blame? As you are arguing, it seems that BOTH Snover and Frosslass are suspect. However, this logic is supremely flawed. You are arguing that Snover is broken because of the support it gives Frosslass to be a general bitch and make life suck in UU, and you say Frosslass is broken because of the general bitch she is to UU under hail. So, you propose to take them
both away. But, without one, the other is hardly as much of a suspect. Without perma-hail, Frosslass isn't as annoying. Without Frosslass, Snover's perma-hail isn't as supportive. So, if we do what you propose, we're banning two Pokemon that rely on each other to be potentially broken, and then we'rre banning a pokemon that isn't even broken anymore in Snover. Snover is only considered broken because of Frosslass. Get rid of Frosslass, the problem is severely lowered, and Snover will not be considered as BL.
So, it's rather easy to see, from a strictly Philosophical view point, that Frosslass is the obvious suspect in all of this, if a suspect has to arrise. Perhaps Snover fits the support characteristics, but it is only for
one pokemon When that one Pokemon is gone, Snover doesn't even come close to the characteristics of a supportive BL. It's really a no brainer. Ask yourselves, "which of these Pokemon is doing more damage? Snover or Frosslass?" And, to determine this, look at what will happen to the other if the one you chose is gone. If you remove Snover, Frosslass is still really close to being BL. If you remove Frosslass, Snover isn't even remotely BL anymore.