It's not a response to 6D... we all know it's a response to D600...
Nikon really dropped the ball with the D800 and D600. Canon have really picked up their game with the 1Dx, 5DIII and 6D. The new 610 specs look very much like a feature plugged responce to the 5DIII and 6D. If it were a response to the 6D, it would have GPS and Wi-Fi. Unless by that, you mean it's a response to the 6D not flinging oil all over the sensor.
... as was the 6d, Canon would have never released it without the pressure from Nikon.
We could (or rather not start) to argue Canon vs. Nikon systems and specs vs. reality all day long, but from what I've seen Nikon's updated camera leaves very little to be desired and the trolling level of some of the posts above proves that Canon die hards are at a loss to find any real arguments :-o
RGB metering, silent shutter, 100% viewfinder, 6fps, f8 autofocus, 39 af points, 24mp ff for under $2000, oh my, this is throwing down the gauntlet.