Sword of the Meek is the most recent in a string of Modern unbans that have failed to live up to the hype that their reputations generated. Simply put, Magic is a different game from what it was years ago when Sword of the Meek, Bitterblossom, and Ancestral Vision were dominant. The powerful token-generation engine falls victim to the issues that every Esper-colored control deck in the format has thus far: not enough cheap interaction to deal with the varied threats that Modern presents.
Sure, Path to Exile costs one mana, but it's hardly a card you want to cast on turn 1 because the tempo gain for your opponent is simply too great. But with the reveal of Fatal Push in Aether Revolt, the promise of viable control decks that don't use Lightning Bolt as their turn 1 removal spell of choice is renewed, so perhaps these sorts of decks can emerge from the fringes to turn Modern on its head.
After all, this list has put up two 5-0 finishes in MTGO Leagues from the same pilot, despite not having Fatal Push yet. The cards are clearly powerful, and the Thopter Foundry / Sword of the Meek engine fits perfectly with Gifts Ungiven, which also gives you a ton of free wins from simply interacting until turn 4 and putting both Unburial Rites and Elesh Norn, Grand Cenobite in your graveyard.
Having an “I win” button is great for control decks in Modern, since you can reliably generate some advantage in the early-game or at least maintain parity. The other issue is establishing a clock so your opponent doesn't have time to draw back into the game with whatever powerful shenanigans they are up to. Effectively ending the game against a huge swath of the format, Elesh Norn lets you have the security of knowing it's in the bag while still letting you draw cards and do a bunch of sweet things with your deck, the control player's dream.
The addition of Fatal Push also makes Gifts Ungiven stronger, allowing you a wider array of targets so you'll always have a good pile to find. I'm a bit surprised not to see at least a single Snapcaster Mage here for that reason, since it's a great addition to any Gifts Ungiven pile, effectively forcing your opponent to give you two cards of your choice if there's an instant or sorcery they cannot afford to give you.
If the hype around Fatal Push proves prescient, then Modern is about to change in a big way, so decks like these will be important to revisit in the coming weeks.