Glaceon can work. She's a fragile sweeper, but with Snow Cloak on your side, she can take a hit or two. I would run Blizzard/HP Fighting with either Wish/Substitute/Fake Tears/Encore to force switches, to help defend yourself.
Glaceon works, but she's not the best choice for a hail team. I use hail so I'd like to say I know what I'm talking about xD
Glaceon is neither fragile nor a sweeper. Mixape 2-hit KOs 252 HP Glaceon with Close Combat or Flamethrower, and Glaceon does not have the speed to pull off a sweeper set.
Granted, in the typical case you don't want Glaceon to stay in against infernape, but anything that can withstand a super-effective hit from both sides of Mixape is certainly not "fragile".
The problem with Glaceon is speed if anything. Even with a scarf, it fails to outrun necessary threats, and that its defenses are just too low for it to tank.