The new standard format for Hearthstone has really changed the way people play the game. Face Hunter used to be the gold standard for aggro, and if you couldn't live through their brutal onslaught your deck was pretty much doomed on the ladder. Now, Face Hunter is almost nonexistent, in fact Hunter as a whole is nearly unseen in competitive play. I like this new way of playing, and not because there are no aggro decks - they exist - but because the aggro decks generally focus a lot more on building a board fast and interacting with the opponent instead of just loading up on 1 drops and burn. If you wrest the board away from them, you probably win.
I have been playing N'Zoth paladin personally and I am enjoying it greatly. It feels decadent to play a deck with three 8 cost minions, a 10 cost minion, and a couple spells you often spend 10 mana on. The deck plans to play really slowly and have super high value plays and I love it. This kind of outrageously slow plan would have been totally unworkable not so long ago and I feel like I nailed that much about my prediction about the effects of the latest content patch - games really are being regularly decided by whose gigantic 10 drop comes down to end the game.
Funny thing I have seen about how decks are described though - they are usually categorized into aggro, control, or midrange. I don't really think midrange describes them properly though, because I feel like they aren't actually trying to win in the medium term. All they are doing is trying to use all the best cards. Control decks have a plan, which is to last a long time and set up a situation where their victory is inevitable. Aggro decks try to seize the board and end the opponent before they can lose their early momentum. Midrange decks, on the other hand, are mostly just a pile of the best possible cards that hope to win based on quality.
That quality isn't a measure of raw card power. If you just want the most powerful cards you play nothing but things that cost 8 or more, and you lose. It is about efficiency, about selecting everything that a class has that is super effective for its cost and then hoping that those cards carry you to victory.
I think it is useful to think about decks this way because you can recognize when your deck has a particular plan and should use cards to forward that plan, and when your deck is just trying to have awesome cards and coast on them. For example, Leeroy Jenkins is a card that you use when your plan is to do 30 damage before giving up the game completely. On the other hand Excavated Evil is a card that you use when your plan is to just keep the board totally clean until you drop some gigantic monster to win the game. Midrange decks don't use those sorts of cards generally speaking because they don't have such a concrete plan.
In my mind a better descriptor than Midrange would be Goodcard. That is all those decks really are: A collection of the most efficient cards a class has. That isn't a criticism - nothing wrong with putting a bunch of good cards in a deck and just reacting to the situation instead of pushing your plan. I do think it is a more useful way to talk about them though, because it makes it clear that there is a division between decks with a plan and decks without a plan.