That's not how it is. Yes, the numbers on the premium cards are very high and they have dramatic art and all this stuff, but they're not as good as you think. You have to remember to factor in the entirety of the card, not just stop at their high power or crazy abilities. The mana cost is extremely important.
Looking at some premium examples; Maelstrom Angel requires one of each mana to cast. LOL to that, never using that shit. Kozilek costs 10 mana to cast, also lol. Griselbrand is the same, costs too much to be valid. Stoneforge Mystic is a troll inclusion; because she's good but they didn't give her any good equipment to summon. If they had included Stoneforge + Umezawa's Jitte or something, you would be right, but they didn't.
(I haven't looked at every single card. If there's something like Elvish Piper, that could suck...)