I'm not sure you understand what was announced. The VMware Cloud on AWS will use standard vSphere Distributed Switch and NSX overlay networking. This means you can completely control what MAC and IP addresses get assigned to all of your VMs, and can hard code MAC addresses for those troublesome applications that hard-code their license to your NIC's MAC address.

tl;dr In the VMware world you've always had the ability to specify your own MAC and IP address. In VMware Cloud on AWS you'll have the same ability.