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.
Aww...I really like Glaceon...Is Froslass more useful than it on a Hail team? What's a good ev spread for a Spiking Destiny Bonding Support Froslass? I saw your warstory and it looked really sweet...