If this is supposed to be video oriented, it certainly needed to do 1080p@60fps, clean uncompressed HDMI output, and preferably a headphone jack. Plus make sure it has the timecode like the 5d3 does, and other bits and pieces for the video codec in the 5d3. Oh, and as others are saying, phase detect AF similar to the T4i (even though it isn't great, it's something) and a swivel like the 60d. Dual slot (even dual SDXC) would be nice, and definitely the auto-rollover to a new file as needed.
The think I'm pissed about is how they didn't put GPS into my 5d3 (and 1dX). Least they could have done, and maybe if they needed an antenna there would be a cheap way for that to get plugged in. The WiFi I probably wouldn't use, but I can see how it might be useful now and then and I'd have though they would do that for the 5d3/1dX as well. I mean really, the 2 flagship models don't have something like this?
Personally, having shot the 5d2, if I were considering an upgrade the only things that would attract me would be the additional high ISO settings, and if I did video the 720p@60fps. That's it. I doubt I'd 'upgrade' to the 6d from the 5d2, especially since my CF cards wouldn't be compatible. Oh, and are the batteries compatible between 5d2/5d3 and the 6d? I love how they kept the same battery size between 5d2 and 5d3.