If the 15 cards they are talking about right now include Old Gods/LoE/TGT cards then this is probably the list of 15 cards:
Yogg Sauran
Call of the Wild
Doomhammer/Rockbiter
Tuskar Totemic
Tunnel Trogg
477
War Axe (Blizzard is always talking about this card)
Highmane (seems like Blizzard thinks this card is insanely strong too)
Thing from Below
Preparation/Innervate (these cards are always talked about at Blizzard)
Azure Drake (no support for this but I can tell you that statistically this is probably the most played card in HS right now so Blizzard is probably talking about it in some capacity)
Barnes (probably not talked about too much as it's a new card and not explored as much but it hit the Firebat ban list so it's probably on the talking table regardless)
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Yogg: needs to be nuked from orbit. The number one problem currently in the game and probably in the top 5 worst ever.
Call of the Wild; I'd make it cost 9. King Krush costs 9 and is a worse card.
Doomhammer: Just make it so it can't combo with Rockbiter.
Tuskarr Totemic: Summons Basic Totems Only. (still good with TFB, Primal Fusion, but doesn't blow games out on turn 3)
Tunnel Trogg: Meh. Lots of midrange Shaman decks aren't even running it. If they adjust this, then they need to do the same to Mana Wyrm.
Flamewreathed: Meh.
War Axe: Unlikely to get adjusted, as it really hurts the only high-tier control deck in the game. Tempo Warrior/Dragon/Pirate Warrior are out of the meta anyway, so War Axe is being used honestly, to slow down the game, and not to snowball early tempo which was I believe the issue with it.
Highmane: Better than any Hunter legendary. Not sure I can be neutral on this one because Highmane and COTW are so punishing to Control Warrior, which is a deck I like to play sometimes.
Thing From Below: Sure? It's OP as heck but I don't think they are going to adjust every single good Shaman card. It's still funny to me looking at this and then looking at the Druid card Knight of the Wild.
Prep/Innervate: You'd have to rebalance a lot of Rogue and Druid if you touch these cards--which they probably should. Cheating mana is really strong. But with Yogg nerfed and Rogue bad, what's the incentive to deal with these cards now?
Azure Drake: Super unlikely. I'm fairly disillusioned with their current direction of making underwhelming neutral cards and very powerful class cards. Having good neutrals isn't a bad thing, and Drake isn't the auto-include BGH, Owl or Shredder was.
Barnes: Maybe because it constricts future design space, but I don't see them making a change to this card so early in its life when it's lost popularity in everything but midrange hunter.