The CR3 confirmed specs are unfortunately not enough for me to upgrade from 5D Mark II...
I'm sure the new 5 series camera will be great and if I didn't own Mark IIs, I wouldn't hesitate on the purchase but, I ask myself; what will I get in return for the $3500?
+1MP? Not worth the trouble...
Super-duper ISO performance? Don't care under studio lighting...
7fps frame rate? Irrelevant...
+0.2" LCD? No use for me...
61 points AF? I'll still be using center AF point if it had 661 AF points.
That would be $3500 spent for everything I don't need so I definitely see no point in upgrading.
Do I even consider switching to Nikon for the D800? No, not at all. I've invested too much in Canon gear to switch now. Plus, today D800 appears to look like what I need but what happens tomorrow, you never know...
I don't know if it's wishful thinking but somehow I believe that Canon will also announce a camera aiming at studio/landscape photographers, weighing heavier on the megapixels rather than low light capability and speed.