I'm not too sure what they could add. They aren't going to unlock RAW output for video or 4k. They already unlocked HDMI out, granted it isn't perfect.
I just got a 5D3 and it already has all the various Servo AF tracking modes like the 7D2. I don't think we see anything earth shattering on a 2.0 release with the 5D4 being imminent.