WotC made it clear that they want to provide some solutions against ramping in EDH, in form of Tectonic Hellion (against land ramps) and Dockside Extortionist (which does way more than catching up). Extortionist is awesome, that goes without saying, but Hellion is 7cc and may hurt yourself if you land-ramp. Granted, a Boros deck would likely ramp with artifact than anything else, but it's still either too early or too late against land ramps. So what else can Wizards do?
It makes sense, since Zendikar residents have affinity with land drops, Eldrazi being its primary adversary should have anti-land mechanics. And because Eldrazis are mostly colorless in cc they could go into any deck. WotC could make Eldrazis that hinders land drops and it'd be well within flavor and convenience of players. For example:
Eldrazi Blightspawn
3
Creature - Eldrazi
2/2
Whenever a land enters the battlefield under an opponent's control and that player controls at least two more lands than another player, that opponent returns a land they control to their hand, then exile the top card of their library and a card in their graveyard.
If target opponent controls at least two more lands than any other player, create X 1/1 colorless Eldrazi Scion creature tokens, where X is the number of lands that player controls. They have "Sacrifice this creature: Add C."
-----
And if they're with devoid:
Black Eldrazi Punishment 2BB
Tribal Sorcery - Eldrazi
Devoid (This card has no color.)
If target opponent controls at least two more lands than another player, that player reveals their hand. You choose X cards from it, where X is the number of lands they control over another player. That opponent discards those cards.
Blue Eldrazi Punishment 2UU
Tribal Sorcery - Eldrazi
Devoid (This card has no color.)
Gain control of target permanent an opponent controls with cmc X or less, where X is the number of land they control.
Rred Eldrazi Punishment 2R
Creature - Eldrazi
3/1
Devoid (This card has no color.)
Whenever a land enters the battlefield under an opponent's control from a library or a graveyard, that player puts a nonland permanent they control on top of their library, then shuffle it.
White Eldrazi Punishment 2W
Creature - Eldrazi
1/3
Flash
Devoid (This card has no color.)
Whenever one or more lands enter the battlefield under an opponent's control and that player controls at least two more lands than another player, those lands enter the battlefield tapped, they do not untap during that opponent's next untap step.
Lol, I should look into that.
Shu Yun, the Silent Tempest WUR Voltron Control
Temmet, Vizier of Naktamun WU Unblockable Mirror Trickery
Ra's al Ghul (Sidar Kondo) and Face-Down Ninjas
Brudiclad, Token Engineer
Vaevictis (VV2) the Dire Lantern
Rona, Disciple of Gix
Tiana the Auror
Hallar
Ulrich the Politician
Zur the Rebel
Scorpion, Locust, Scarab, Egyptian Gods
O-Kagachi, Mathas, Mairsil
"Non-Tribal" Tribal Generals, Eggs
Sire of Stagnation and Oblivion Sower came to mind.
It makes sense, since Zendikar residents have affinity with land drops, Eldrazi being its primary adversary should have anti-land mechanics. And because Eldrazis are mostly colorless in cc they could go into any deck. WotC could make Eldrazis that hinders land drops and it'd be well within flavor and convenience of players. For example:
Eldrazi Blightspawn
3
Creature - Eldrazi
2/2
Whenever a land enters the battlefield under an opponent's control and that player controls at least two more lands than another player, that opponent returns a land they control to their hand, then exile the top card of their library and a card in their graveyard.
OR
Colorless Eldrazi Punishment
4
Tribal Sorcery - Eldrazi
If target opponent controls at least two more lands than any other player, create X 1/1 colorless Eldrazi Scion creature tokens, where X is the number of lands that player controls. They have "Sacrifice this creature: Add C."
-----
And if they're with devoid:
Black Eldrazi Punishment
2BB
Tribal Sorcery - Eldrazi
Devoid (This card has no color.)
If target opponent controls at least two more lands than another player, that player reveals their hand. You choose X cards from it, where X is the number of lands they control over another player. That opponent discards those cards.
Blue Eldrazi Punishment
2UU
Tribal Sorcery - Eldrazi
Devoid (This card has no color.)
Gain control of target permanent an opponent controls with cmc X or less, where X is the number of land they control.
Rred Eldrazi Punishment
2R
Creature - Eldrazi
3/1
Devoid (This card has no color.)
Whenever a land enters the battlefield under an opponent's control from a library or a graveyard, that player puts a nonland permanent they control on top of their library, then shuffle it.
White Eldrazi Punishment
2W
Creature - Eldrazi
1/3
Flash
Devoid (This card has no color.)
Whenever one or more lands enter the battlefield under an opponent's control and that player controls at least two more lands than another player, those lands enter the battlefield tapped, they do not untap during that opponent's next untap step.
Shu Yun, the Silent Tempest WUR Voltron Control
Temmet, Vizier of Naktamun WU Unblockable Mirror Trickery
Ra's al Ghul (Sidar Kondo) and Face-Down Ninjas
Brudiclad, Token Engineer
Vaevictis (VV2) the Dire Lantern
Rona, Disciple of Gix
Tiana the Auror
Hallar
Ulrich the Politician
Zur the Rebel
Scorpion, Locust, Scarab, Egyptian Gods
O-Kagachi, Mathas, Mairsil
"Non-Tribal" Tribal Generals, Eggs