One thing that's being overlooked here is the fact that a Hail team can benefit from hail, but doesn't necessarily have to RELY on Hail. In fact, in my opinion, relying on Hail is a very bad move considering the prevalence of Abomasnow killing Pokemon (of course, it's important to note that if played correctly, Abomasnow kills pretty much anything. It's the speed that makes it get shredded by popular Pokemon such as Genesect). I've found that the biggest help to a Hail team is a plethora of status inducers (specifically paralysis) that assist in speeding up the overly slow Ice-types. Many Ice-type pokemon, Abomasnow and Kyurem being the first two that come to mind, can't deal with the absurdly fast paced current metagame even though they have massive attack stats, making them sub-par. Support from status inducers greatly helps these Pokemon. In addition, utilizing pokemon like Endeavor Mamoswine to set up rocks, endeavor them down to no health, then kill is another possibility. Normally, if you die after endeavoring they're left at low hp. However, with Hail up, they now die too. There are many other similar strategies that could greatly benefit from this bonus damage, the most simple of which being the simple all out offense. The small damage compiles quickly and assuming you have one or two other Ice-types that's a big advantage. Moral of the story: a mixed bag is better than a one trick pony.