With a new lens mount, this is a completely new camera system from Canon. It may be the most significant camera from them for a decade.
The sensor is a 30 megapixel CMOS and the overall design, while obviously retaining the EOS DNA, is completely new.
Video is cropped but is apparently output through a clean HDMI feed at 10 bit 4:2:2, so should look very good when recorded to an external device. Sounds like a good match for the new Atomos 5" Ninja.
Autofocus is Dual Pixel. There's Canon Log recording giving 12 stops dynamic range at 400 ISO. (Maybe a bit less than you'd expect but this is always subjective and different manufacturers test in different ways. In any case this is easily enough for good HDR.)
ISO range is 100 - 40,000.
There's WiFI, Bluetooth and USB 3.1
We're meeting with Canon today and will bring you more news later. Meanwhile, here's Syrp's excellent first-look video.