I think competitive Hearthstone is in a weird spot, especially when you need to bring 5 decks. The classes just aren't equal, so it gets really random when you have to play against a field. You basically have Shaman and Warrior as extremely good consistent decks, then things get weird.
Then you have Zoo which is relatively consistent but needs to dodge your opponent drawing clears and have you discard the right cards.
Then there is Druid, which is good but I think would be better if people just went more ramp style instead of Malygos. It basically wins on Arcane Giants and something like Rag WAY more often then with Malygos. Druid just has the problem of it's hugely consistent on Ramp and draw since the decks can be so awkward, it has the ability to just draw a loss.
Mage and Rogue are in a similar place to Druid, but not as consistently strong. The two decks have a huge chance to draw completely awful and into a loss, but also have some of the best potential in the game that when they draw the nuts it's almost impossible to beat them. Freeze Mage would still be good, but it suffers from auto loss to Warrior, but I feel like it's something people should have thought about just banning Warrior instead of Shaman and playing to that side of things.
Hunter is probably better than it seems, but the deck just runs out of gas too often. It's more a matter of how effectively does your opponent play against secrets than anything you do.
Priest and Paladin are pretty unplayable tbh.
I think what my point boils down to is they really need to focus on giving all the classes something that can be somewhat consistently good.