It seems like once youve ramped into your 4-drops, youll be playing aggressively and attacking your opponents as often as possible
TL;DR: You won't be required to collect as many reprints to fill out your collection
These five cards are held back only by the fact that they are legendary, meaning that you can only have one of each in play, and they do not possess the basic land tag, meaning they cant be fetched by cards like Rampant Growth
Bitter Ordeal Cranial Extraction Denying Wind Dichotomancy Dimir Machinations Extract Haunting Echoes Jester's Cap Kotose, the Silent Spider Lobotomy Lost Legacy Memoricide Neverending Torment Nightmare Incursion Pick the Brain Reap Intellect Sadistic Sacrament Stain the Mind Supreme Inquisitor Thought Hemorrhage Titania's Command
Sometimes it's small effects, like Eager First-Year getting +1/+0 until the end of the turn, to the absolutely ludicrous like Jadzi, Oracle of Arcavios letting you reveal the top card of your library and play it for just one mana
In my opinion, the most important element to understand about Tarkir Limited is that the cards are created unequal