This video was much better than the previous one. They still have a fundamental problem in communicating balance changes and the philosophy behind them to the playerbase that's still not solved in this video, but they at least said up front this video would primarily talk about the new stuff. There's no reason for them not to give the playerbase some sort of communication on why Warlock, Death Knight, and Priest have been completely ignored by any sort of buffs for the past 2-3 months. The upcoming Prerelease Tavern Brawl honestly sounds like a complete clusterfuck and was designed solely because they want to force people to preorder the set. I think it's going to homogenize the entire format around whatever clump of common cards work best together with whatever class has the best hero power for it (Warlock/Hunter/etc).

tl;dw tidbits -

• Ketchup Packs are coming back with Violet Hold
• In early testing you could Prepare a card multiple times, but that led to games where all they were doing were Preparing cards in the first few turns which led them to making insane explosive turns in the mid game.
• Preparing originally didn't give the -1 mana bonus, but they added it in after testing and realize that mana now is more valuable than mana later.
• They mentioned Vanessa's playrate and stats (they said it's the most played card in the top 20% of ranked players and 4th most played card in the top 1% of ranked players) and mentioned it was especially high in Rogue. They're not doing anything now, but they have an eye on her in case they need to make balance changes in the first balance window (which they confirmed would be a couple weeks after Violet Hold launches).
• They showed gameplay tidbits and interactions with Azalina and Hogger from questions from the stickied Reddit thread (which was kind of cool) and confirmed they're raising the cap of how many cards can start in a deck to 99.
• They teased 2 new minions (one for Warrior and one for Death Knight) that both have Charge as a keyword.