Okay let's look at the card so far.
Druid
Kun the Forgotten King: Very interesting idea but tempo is the King of this game right now so I don't know if you can still win the game by turn 10 Even with Druid but probably pretty good for arena.
Lunar Visions: Should be really good for big minions
Pilfered Power:...I feel like blizzard is trying to kill aggro decks with a nuke at this point, Which I totally approve of. Seriously this is kind of ridiculous. Especially since it's kind of easy for him to pile up small minions at the beginning.
Mark of the Lotus: Look another OP card, I mean holy shit blizzard calmed down Druid wasn't that weak
Hunter
Piranha launcher: Unless they are releasing a card to synergize well with, this weapon is pure garbage.
Mage
Manic Soulcaster: So you put down a Spider Mech and get a copy of another card, That's pretty good.
Paladin
Wickerflame Burnbristle: Looks like a pretty interesting card but I'm not sure if it would fit in the meta, especially since Paladin has all the heals in the universe
Small-Time Recruits: Seems boring but practical, especially for shield Paladin
Meanstreet Marshal: I can't see this card being played that much, It seems like too much work to get one card.
Getaway Kodo: oh good Secret paladins coming back isn't it? I'm just going to go cry in the corner now.
Priest
Dragonfire Potion:...So I think blizzard listen to us about priest.
Drakonid Operative: Considering that Dragon priest was just made a thing again, I can see this being played, Especially since it has really good stats.
Pint-Size Potion: I like To call this card the "fuck you aggro decks", Not sure it will be enough but it's the thought that counts.
Kabal Talonpriest: The priest card we've been asking for, seriously priest needed a Good three drop.
Potion of Madness: I can see this card being decent especially mixed with pint-size potion
Rogue
Lotus Assassin: They just want to straight up murder Agro decks, don't they? but all seriousness this looks like a pretty good card.
Counterfeit Coin: Looks really good especially for combo decks.
Warrior
I know a Guy: An okay card for the most part, I think I'll do well in arena
Multiclass
Lotus Agents: Decent ability, absolute garbage stat line
Grimestreet Informant: A okay stat line and an extra card is pretty sweet.
Kazakus: It seems absolutely awesome but sadly very impractical But hey Reno look like that and that change the meta.
Kabal Courier: Same as the other two, okay ability but weak Stat line.
neutral
Finja, the Flying Star: So an auto-included In every murloc deck then...
Patches the Pirate: Seems like a pretty good card but it depends if Pirate finally becomes a thing
Wind-up Burglebot: Too much mana and to weak to see any play.
Fel Orc Soulfiend: meh is all I can say about this card
Big-Time Racketeer: Interesting card but I'm not sure it really fits.
Second-Rate Bruiser: There trying to destroy Agro deck's very soul so they can never come back again aren't they? once again I 100% approve
Kooky Chemist: Considering that his smaller brother doesn't see play I don't think he will either.
Friendly Bartender: A decent effect and a decent stat line, good for arena and constructive
Mistress of Mixtures: aka The new zombie chow.
Overall these cards a really sweet and I'm excited for this expansion.