A better way to argue Froslass's unbrokenness is showing how there are certain Pokemon that can deal with it without being overly worn down. Snunch mentioned Rapid Spin / Roar Blastoise; WinstonSchnozwick presented Cobalion and Registeel. If there are enough answers that can be used against Froslass, then that would more validly prove that Froslass is manageable than playing with numbers.
OK.I can agree to that as it is a very reasonable request.Off the top of my head and with no calcs (so correct me if it doesn't take it as well as I think) I can think of:
Slowbro/Slowking - Don't mind speed drop from para,Regenerator/Slack Off for Spikes/Hail,resist Blizzard,could possibly set up Calm Minds
Suicune - Resists Blizzard, easily use Rest for Spikes/Hail,Pressure to stall out Blizzard, Calm Mind for better sponging
Milotic - Gains boost from TWave,Resists Blizzard,Recover or Rest for healing
Lanturn - Immune to TWave, high Sp.Def and resists Blizzard
Gastrodon/Quagsire - Immune to TWave,Recover for healing (Not sure since nuetral to Blizzard)
Clefable - Immune to passive damage, Softboiled or Wish for healing,possible Calm Mind
Chansey - Wish for healing self+team, Aromatherapy to heal TWave off team, Natural Cure (Iffy since it seems like Hail+Spikes could wear it down)
Empoleon - Quad resists Blizzard,Flash Cannon for SE or Roar to phaze,Won't mind para as it is either Sp.Def bulky or SD+Aqua Jet
Registeel - already mentioned
Mew - Has reliable healing,has acess to Roar/Taunt/Heal Bell/Light Screen to deal with it, possible Synchronize (doubtful)
Deoxys D - Pressure to stall Blizzard, Recover for healing, has acess to own hazards or screens
Rotom H - Resists Blizzard, no spikes damage, defensive sets won't mind para while Scarf sets can either Trick/Overheat a Subless Froslass or Volt Switch to break a Sub.
Snorlax - Thick Fat,high Sp.Def,usually has Rest to recover Hail/Spikes
I'm sure some of these don't entirely work and some probably work alot better than others but that's some initial thoughts.All of these assuming standard Hail set of TWave/Sub/Spikes/Blizzard.