The major problem with Mage is the style of play doesn’t play well with the design of Hearthstone.
Hearthstone was designed as a minion based board control game. Taunts and other things were designed with that expectation in mind.
When you make a spell heavy class, you are playing a part of the game as your main arsenal and the other part of the game can be ignored. Imagine playing Monopoly but you no longer are playing to grab property and build hotels and houses and instead you’re focused on amassing a win via Chance and Community Chest cards.
The game doesn’t have a lot of anti-spell stuff, but it has a lot of anti-minion stuff. That’s why Mage design feels bad to lose to, because you don’t feel like you’re losing to the basic principle of the game.
This isn’t the fault of Mage players. It’s the fault of the design. If they want spells to play a major role in the game, and indeed base an entire class around casting spells, they probably should have designed the game a bit better to allow interaction with it. I can come up with a thousand different clever ideas of what this would look like, but ultimately we have what we have.
Because of this, it’s very easy for that spell based class to quickly become a problem or quickly be garbage.
The game wasn’t designed in a way to be ‘spell friendly’. What I mean by this, is that if I said I had a 10 damage minion that can hit your face, what can you do about it? Well, I have a turn to prepare. I can kill it with a spell. I can taunt it. I can kill it with a minion. I can bounce it back to your hand. I can do allllllllllll sorts of things to it (dormant it, shuffle it into your deck, make it miss its attack, etc etc etc)…there’s a LONG list of things you can do to a minion. And, you get to prepare (assuming no charge).
Now what can you do against a spell that’s cast from hand and deals 10 damage to your face? Well…the list is much much smaller than it is for a minion. The list is extremely small on what you can do to stop it.
That’s the main problem. That’s why the spell/minion thing is not balanced. Now I understand it’s not balanced because a spell is used and gone, and a minion lasts until removed, but that’s exactly part of the imbalance.
Things like this in other games are balanced around the opponent being able to react and balanced around an interaction of players. Most card games have interactions with each other on each other’s turn. The inability to react to your opponent in this game on their turn is a massive limit in design, and it’s part of the problem why losing to a chain of spells sucks - you can’t do anything about it or your options to do something about it are so miniscule.