"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
AirPods and AirPower: Everything We Know
Steve Jobs on Lack of Firewire in MacBooks
Actually, all of the new HD camcorders of the past few years use USB 2.Whether or not you agree with Apple's decision to remove Firewire from its low end laptops, it's clear that Apple is abandoning the feature in their consumer-targeted machines.
Apple helped to develop Firewire in the 1990s and still offers Firewire support in the rest of their Macs at this time, with the notable exception of the new MacBooks.