The best sacrifice outlets are going to be your cards that let you sacrifice a creature at instant speed and preferably with no cost
Polymorph effects will always encourage players to try degenerate builds, and I dont think that Lukka really deserves criticism over that
This is great in Red-centered Spellslinger Brews that cast instant and sorceries to trigger things like Young Pyromancer and Guttersnipe like Izzet, Boros or Jeskai
Expect to see many two-color decks in Standard thanks to this card
You can give gifts to curry favor with your opponents, trading cards or counters for promises of temporary truces or protection
Multiple factors converging simultaneously: The Pokmon Company's aggressive overproduction creating supply gluts, too many chase card variants diluting collector attention, macroeconomic pressure reducing discretionary spending, and speculation fatigue after years of unsustainable growth