What the heck blizz?!

So i log in eager to buy Malthael, and one of his skins, because they look pretty cool, and also they are rare, so definitely worth the shards. Lookin at the colors and trying them for 10 minutes, i decide to buy the frozen one, because it looks really cool, only to see that it is EPIC?

How is every single other skin rare, and this one EPIC costing FOUR TIMES as much (150 vs 600)?! Dont want to be whiny, but this skin is not epic quality... If it is epic because its "better" colored, then why is angelic or timelost not epic? I dont think this is right, i've never seen the same skin with different prices.....