> At the very least, a secure IPv6 network will need to hide end user addresses somehow, because giving everyone a unique, globally-addressable and trackable ID

> At the very least, a secure IPv6 network will need to hide end user addresses somehow, because giving everyone a unique, globally-addressable and trackable ID is a security showstopper. this is a solved problem now. All modern OSes either create short-lived temporary addresses or they hash some machine-unique information with the public prefix (that will change in the same frequency as your current V4 address changes).