Last December, I was told by someone who "should know" that the Mavic II (or whatever it will be called) will be announced in 2018 Q2 and released in Q3 or Q4.
Whether my source is right or wrong, a new updated Mavic-like quad is inevitable, by DJI and others. As the state of the art and competition develops, we will see at least: greater range; higher speed; better camera; all-around, close-quarter OA (especially in "follow-me" mode); longer flight time; more sophisticated intelligent flight modes; centimeter-accurate GPS; redundant "find-my-drone" systems; mission-complete and RTH upon loss of signal.
A few years may pass before we see all this stuff, and maybe not all on the same drone. But we all know they're comin'. Gives us something to look forward to as we enjoy today's Mavic.