Stickers were something we knew would be in the set from day one, and we spent a lot of time experimenting with different ways of using them
We also had the reprint of key dredge cards like Dakmor Salvage and Life from the Loam in recent Commander precons ( Edge of Eternities Commander and Tarkir: Dragonstorm Commander , respectively)
It's like turning our dead cards into undead cards
Also of note, Kykar triggers on every noncreature spell you cast, not just instants and sorceries, meaning your mana rocks and supporting enchantments will make Kykar just that much more useful
Rules text, reminder text, italics, flavor text, power and toughness, and sometimes all of it on one card that already does too much
It also gives you much more control over the rummage effect, letting you hold onto cards you want to keep