I wonder what scientific analysis there exists for these kind of things. Surely some mathematician with too much free time has sat down to tackle this thing, not to solve it, but at least to gain some insight into it.
card game balance is too broad of a topic (and asymmetry is a very difficult topic to tackle), but the deck construction can usually be reduced to what is essentially a handful of different tradeoffs
every resource-based card game (i.e. MTG/hearthstone, as opposed to gwent) is basically doomed to have balance problems. the key is what each game does to mitigate them
constructed mtg allows ~30% of your spells exist in sideboard for best of 3 matches
mtg sealed requires people to build their own decks instead of copy a list
mtg draft has a self-regulating property where stronger colors will have more competition (and draft pods have an extra layer of protection against imbalance)
this basically allows wizards to make some amount of mistakes without killing the game
blizzard basically ignored all of the above (and has much less counterplay in general), so any balance problem has a much larger impact