I appreciate your optimism, but I think you are totally wrong about certain decks having unfair advantages.

The top 5 decks on ladder and tournaments are mech mage, druid, hunter, rogue and paladin. All of these decks have a strict win condition, which are both unfair and class specific.

Mech mage - you already addressed this and I agree

Druid - combo and innervate.

Paladin - Muster, Quartermaster and equality to counter.

Hunter - Savannah Highmane and scientist/freezing trap for tempo

Rogue - card draw and stupid burst.

It is no surprise that 80% of the meta are playing these decks, and playing exactly the same 27 cards at least. You can reliably pull off the win condition at least 1 in every 3 games, which is enough to guarantee a positive win rate if you don't suck. Compare this to a deck without an unfair win condition, eg. warrior or priest or even warlock now. These class will straight away lose 50% of their games since they do not have "that play" that wins them the game.

In order for everyone else to fulfill their win condition, they must play the same 27 cards as the netdecks. This is no different to any other time in hearthstone, maybe it is nice that there are now 5 classes that have the unfair advantage, but it just means instead of playing against miracle over and over, now you play one of 5 different classes. You still know exactly what cards they are going to play, you know what they are trying to do, you may or may not be able to counter it, but ultimately you are just trying to pull off your win condition before they pull off theirs.

I think all of the above cards should be nerfed, along with regular nerfs at least once per season. THEN the meta might finally see a bit of variance and experimentation in decks. For now, we just play against the same 5 decks over and over and feel bad for that guy trying to play priest.