I have just posted a bunch of slides from a corporate dog and pony show and started working on it for gaming. If the server core with 16 threads can be delivered to AM4--Intel would definitely be spun around with a new rival for gaming processors.
While M.2 has been bolted onto onto AM3+ boards the new AM4 will feature this on all boards.
M.2 will make life easier for FreeNAS etc as the USB stick can be tossed for a flash card on the board.
I still play LEFT 4 DEAD 2 » HARDCORE GAMES™ and it fits M.2 drives on the market easily. Other games can be installed to a hard disk
SATA SSD are now up to 4TB which will pressure M.2 considerably. Still have not noticed much for SATA Express.