Seems they're aware of this and like it that way. The Ice gym leader says Ice is extremely tough (which is true -- offensively, it's one of the best) but extremely fragile (also true -- one of the more vulnerable types, as you said).Yeah. I think I'll just go with Mega Aggron instead for my bulky wall... which sucks, since Bergmite is one of my favorites this gen.
I really wish Game Freak would've given Ice a defensive buff this gen. Four weaknesses with only one resistance? Hail is also worthless, and freezing is incredibly rare. It's one of my favorite Pokémon types, but sheesh.