Alot of people are saying that M14 is a very underwhelming expansion compared to how good Modern Masters is. I only saw a few cards in M14 good enough to be great in EDH/Commander and other formats like the new Garruk, Strionic Resonator, Imposing Sovereign, Path of Bravery, Dark Prophecy, Mutavault, and my personal favorite Ajani's Chosen. The new Chandra isn't bad but she's mainly good for her middle ability to exile the top card of your library while you still have to pay the casting cost of the exiled card unless its a land.
Incase you're wondering about the art on the new Slivers of M14, If you've payed attention to what happened with the Phyrexian takeover of Mirrodin that sums it up right there. Slivers were originally created by Volrath and the Phyrexians dating back to the Urza block and before. With the new Sliver's in M14 they might have a chance to shine in Modern format especially since it's so good with AEther Vial and Intruder Alarm which is still Modern legal as well. There are a few Enchantment related cards in this set which hints towards Theros block being Enchantment based.