Call of Duty Advanced Warfare is breaking from the Call of Duty formula in several ways. Among them is the omission of a KEM strike or nuke.
A professional Call of Duty player shared footage where he played up to a 30 killstreak. At 20, 25, and 30 kills, he earned a medal, but no KEM strike or nuke occurred. It is possible that a KEM strike or nuke will be added into the final build, but for now, there is no reason to expect it in Advanced Warfare.
If you pick up a gun with a built in attachment, and you want to add two more attachments to it, you will still have to use Wildcard. Each Wildcard costs you one allocation point each. As fans in this thread point out, Sledgehammer retained the need for Wildcards and allocation points to keep the guns, and the game, balanced.
Balance is also the reason the perk Toughness was modified for Advanced Warfare. A fan asked Sledgehammer head Michael Condrey why they kept Toughness, when Dead Silence was taken out. Condrey replied that Toughness is no longer a must have perk in Advanced Warfare. Condrey also asserted that a lot of players will go out of their way to earn the perk, but there will also be players who will opt out.
Call of Duty: Advanced Warfare will be released on November 4, on Windows, PlayStation 3, PlayStation 4, Xbox 360, and Xbox One.