Peacekeeper is only good against merfolk/decks with zero removal. And if peacekeeper see's a lot of play, you can bet that the merfolk players will adapt to fight peacekeeper. Mono blue merfolk has echoing truth and wipe away. Ub merfolk could just pack smother, doom blade, any number of removal spells to kill peacekeeper. Peacekeeper is not that good now that survival is gone; to me, it should just go back to being jank again, now that survival is gone. Where was peacekeeper when survival had not yet surfaced? No one had even heard of the card and if they did, thought it was jank because zoo bolts it, goblins warren weirdings' it or gempalm's it or flings a goblin at it with siege gang or they fling a ton of goblins at your face to kill you. Swords is the better card.

And perish is amazing; it kills goyf, knight of the reliquary, all of new horizon's creatures, elves, wild nacatl, qasali pridemage...the list goes on. The card is amazing. It even kills progenitus and argothian enchantress lol. I don't see a reason to not run it unless your entire meta is combo, goblins, and merfolk.