I think people are missing a HUGE part of Hail vs Sandstorm.
Ice Body =/= 1.5 Sdef boost.
Ice Body, with protect and substitute give a Pokemon the ability to PERMANENTLY, at the most take 1% Damage per turn. Walrein has the defensive stats to pull this off, as there are a shit ton of pokemon it can set up subsitute on. You need to attack this thing 75 times on average to kill it, without sacrificing a pokemon, and you need to HAVE the right pokemon. It also needs to have leftovers, and be immune to Toxic. SDef boost is a GREAT aspect to a metagame. Its really a clever thing, while not being broken, like walrein+hail.
32 times would be the accurate number, and one hit would be all that you need to kill an unsubbed Walrein. And while it is nice to have an immunity to toxic, it's not necessary to have it. Any resttalker not weak to Surf/Blizard will have no trouble whatsoever outstalling Stallrein. That's not even taking into consideration the ways the_arctic_one suggested about dealing with Stallrein.
7ay, in your post especially, you forgot another main point. Sand Veil on a Slow ass terrible defensive typed pokemon with spikes is NOT broken. Froslass can be taunted by like 3 Pokemon, most of them getting OHKOd by Blizzard. Froslass is ALOT better in any case then a pokemon who does not even receive the secondary benefit of Sandstorm, being the SpDefense Boost, but Froslass can still Blizzard for 100% Accuracy.
I think it really shows the lack of thought people put into this topic when they start comparing Sand Veil on an terrible spiker like Cacturn, to Snow Cloak on an amazing Spiker such as Froslass. Froslass can even Block rapid spin for itself.
Who said anything about spikes? Cacturnes abuse Sand Veil by outspeeding walls and subbing until the opponent misses so it can SD up and Focus punch/Seed bomb everything to death. Spikes have no place on a Sand Veil abusing Cacturne
Also, dont bring Rain and Sun into this arguement, they are NOT permanent weather effects.
Yes, comparing Sun and Rain to Hail is a poor comparison. However, saying that Hail/SS is better than Sun/Rain just because Hail/SS lasts permanently is incorrect. Sun/Rain are used purely offensively, the weather sweepers only need enough turns to run through an enemy team. Hail and Sandstorm are more stallish in nature, which is why they need to be permanent weathers. In short, a Sun/Rain team is powerful in spite of its limited number of turns with weather, while a Hail/SS team just isn't viable without permanent weather.
For people who disagree with Snover also, i want to hear how you can deal with Walrein, while not having to pack a hail counter.
People can't deal with Gyarados without packing a counter either, both of these things must be too good for their metagame.
People see Raikou and Hail less, because they are testing new stuff.
Edit: @ 7ay, the fact that you thought of a team that would effectively counter hail shows overcentralization.
What 7ay did was metagame against the threat of hail teams. Metagaming is not overcentralization, it is simply people adapting to a threat. A Pokemon or team should only be considered overpowered in the event that the metagame's reaction is only a semi-counter like in the case of YacheChomp.