Playing fair cards was never intended for such a game. Sure, you can play a 1/3 on 1, 2/3 on 2, 3/4 on 3, 4/5 on 4, but is that the game you really want to play? It's not called Vanillastone.
Yes, cheating mana is a bit annoying, but there are classes that don't cheat mana and still do well:
Pirate Warrior, Handbuff Paladin, even Burn Shaman is playable to some extent. And the point of decks is to find synergies that push the capabilities of a deck to the extreme.
Sure, the argument can be made that some cards are so powerful, that decks are pretty much pre-determined and have no room for innovation other than 3-5 cards. But that's how every meta evolves eventually, people fine tune decks to a point that there is nothing left to optimise.
But it's still better than figuring out how to trade a board of shitters into another board of shitters. I know people like to believe that they will outwit their opponent through efficient trades, but that is not the case once you hit diamond. People know how to trade by then, it's a very basic thing to learn. I pretty much prefer knowing your opponent's deck, and playing smartly around an upcoming blowout turn for them. Tavish questline reward coming down? Make sure you stick a board to prevent it from being played without any punish. Big discounted mech turn coming up? Make sure you save that board clear. Facing control warrior? Make sure you make it as awkward for them as possible to remove your threats, or hold a lot of cards for an OTK burst.
There are much more interesting plays and interactions than "do I trade my 1/3 in the 1/1 or in the 2/1?" And thank the devs we have variety in terms of class playability.