I guess mean in a more drastic fashion. I either might not be able to explain what I mean or it already exists and I don't notice it.
Best way to explain what I mean is that whenever the meta changes, I'd hope there'd always be new decks added over already existing decks that just shuffle around new cards. Patron Warrior is good example. A deck like that never really existed till BRM. Compare that to tempo Mage which appeared now and then but gained popularity with the addition of a few cards.
However, the more I think about it, the less I understand what in trying to get at.
I think I understand what you're saying, but Super Nothing is right. Blizzard has down a good job of introducing cards that shake up the meta or offer new decks/classes a chance to shine. Here are a few examples:
Mid Range Paladin: GvG dragged paladin from the bottom of the ranks to the top for multiple seasons. Quartermaster means your opponent must deal with your 1/1 tokens or they risk losing the board. Shielded mini bot gave them a minion to deal with aggro decks. Muster for Battle gave them a Turn three control card that combos well with lots of other cards.
Tempo Mage: A spell focused mage was tried by everyone thanks to Mana Wyrm & Sorcerer's Apprentice being perfect for it. It took about half a dozen new cards to come out before it could really take off though. Mad Scientist, Flame Waker, Spare Parts from mechs, Unstable Portal, and new damage spells.
Mech Mage: At a time when Freeze Mage seemed to be the only good deck for the class, GvG introduced a board flooding, fireballing, monster. The new tribe and mage reach comboed really well and a new deck was born.
So don't worry too much about Hunter & Warlock hero powers overshadowing the other classes. Plenty of cards have come out that more than help balance the options.