Yes, but the 7D2 can already do 10FPS with dual digic6... Surely dual Digic8 could do better. Plus, when shooting video the sensor is read 60 times per second.
I suspect that a large part of the speed problem is A/D settling time. When you are shooting stills you are generating 14 bit RAW files, and that means using a 14 bit (or higher) A/D chip. When you shoot video you do not need the same colour depth so you can clock it higher because you are not using the lower precision bits anyway.
(I am going to make up the following numbers to demonstrate the concept)
Lets say you have a 14 Bit A/D chip that is designed to run at 1Mhz. If you run that chip at 2Mhz, you will still get a digital output, but (lets say) the last two bits are now random noise.... but you don't really care because all you really want for video is 8 bits, so the 12 accurate bits are good enough. You might be able to push that same chip to 3 or 4 MHZ and still get your 8 bits of data for the video.
And yes, the mechanical mirror will be part of the reason for the slower frame rate, but just getting rid of it is not enough. If Canon rerally wants a high framerate monster it will take lots of computing power and massively parallel A/D on the sensor itself. I think that it is coming, but I will not hold my breath while
I wait.