It’s been a while since a Standard-legal set has had such a big impact in Modern. Kamigawa: Neon Dynasty has almost felt like a baby Modern Horizons. The mechanics of the set, reconfigure and channel, synergize with cards that are already dominating Modern.
Thanks to reconfigure, Hammer Time can now use its Stoneforge Mystics to grab graveyard hate or card advantage. Big creatures that discard themselves make Living End players very happy, and the channel lands are going to be a “free” inclusion in lots of decks. For most decks, this will just be minor upgrades, but for the Wrenn and Six decks, these cards are a game-changer. The best-case scenario used to be building your own Phyrexian Arena with a cycling land and a Wrenn. Now, you can rebuy Unsummons and Disenchants with your Wrenn. These are the biggest additions to Modern but there are many cards that have a chance to see some Modern action.
When the set was spoiled, the consensus was that Lion Sash was going to be the biggest addition to the Hammer Time deck. It was an easy comparison to an already playable Modern card, Scavenging Ooze, and it was even and Equipment so you could grab it with Stoneforge Mystic.
The thing is, Hammer Time is not really about the type of gameplay where a Scavenging Ooze is good. We see Scavenging Ooze in decks like Jund Midrange where you would trade one-for-one then slam the Ooze with lots of food in the graveyard and lots of mana available. None of this is what Hammer Time is known for. Hammer Time wants to play a short game, doesn’t want to flood out and isn’t very good at putting cards into the graveyard. You can easily run out of food to grow the Sash. I expect that as the hype wears off we will see players include zero to one copy of Lion Sash in their sideboard. It will primarily compete for slots against Sanctifier en-Vec as a card for grindy matchups and as graveyard hate.