Sure, this is a good swing late game card but it is so useless against so many lists and in the all important early game that it is a pretty bad option in anything bar a sideboard
Cast it early and get some card flow happening
Whether it's because R&D is afraid of making a creature card that's too powerful or if it's likely to break the format if they push it too far, I'm not sure
7/7 Illustrated by John Tedrick Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Legal Modern Legal Brawl Legal Legacy Legal Comp

Decklist: Temur Emerge in 2016 Standard Lashweed Lurker | Illustration by Igor Kieryluk Planeswalkers (7) Jace, Vryn's Prodigy x4 Kiora, Master of the Depths Nissa, Vastwood Seer x2 Creatures (14) Elder Deep-Fiend x4 Emrakul, the Promised End Gnarlwood Dryad x2 Ishkanah, Grafwidow x2 Lashweed Lurker Pilgrim's Eye x4 Sorceries (14) Gather the Pack x3 Traverse the Ulvenwald x3 Grapple with the Past x4 Kozilek's Return x4 Enchantments (2) Lands (23) Evolving Wilds Forest x6 Island x3 Lumbering Falls x3 Mountain Sanctum of Ugin Shivan Reef x4 Yavimaya Coast x4 Sideboard (15) Emrakul, the Promised End Gnarlwood Dryad Sanctum of Ugin Eldrazi Obligator x2 Reality Smasher x2 Tireless Tracker x2 Learn from the Past Pulse of Murasa x2 Radiant Flames x2 Titan's Presence This deck was a popular one played in Standard at Worlds in 2016, making the most of the power of Elder Deep-Fiend