It looks like the video (and the presenter's description of some things like Research Pacts) are several months old.
Yes, its an E3 video, (the one from the closed demo), (or very similar). Probably made from the same time, however it just wasn't released till now. It is indeed old, for example the desert tile shows no yield when hovvered over, which perhaps was how they first planned deserts to be like, (like civ4), although in newer builds we see they give yields closer to that of grassland. Maybe just 1 less food.
More interestingly than the shrinking city is the fact that the Nuke destroys 2 hexes out from the center

. Not center - 1 hex out but center - 1 hex out - 2 hexes out.
So 19-tile destruction nukes!
This was already confirmed, I believe from Civilopedia Screen Shots done by Azzazel or maybe someone elses Civilopedia Shots. Showing Atom Bombs have a blast radius of 1. (center plus 1 hex each direction), Nuclear Missiles have a blast radius of 2. (Center plus 2 hexes in each direction).
The Nuclear missiles have 2 less range (I think it was 9 & 7 (or 8 & 6) anyway), and I believe from new evidence from somewhere I forget where, Nuclear Missiles cost 2 Uranium, (which is unprecidented, everything else known so far only costs 1x resource.) Nuclear Missiles also are described to "Destroy Units and Damage or Destroy Cities" Where as Atom Bombs differ with a "Damage or Destroy Units & Cities", meaning the Nuclear Missile will always kill all units in the blast area.
Basically its one bad-ass weapon of mass destruction, but its not overly powered with a double cost of Uranium and lower range than the Atom Bomb. Atom Bombs certainly won't be useless when Nuclear Missiles come about, but they are certainly the weaker cousin to the Nuke.