No, it really did not change.
I hear what you are saying. The way it was worded was confusing, and misleading. Deceptive, to be real honest about it. I would have never let a press update go out the way that was worded like that. If you did not know the bike, before, it would have sounded like a new addition, but it was not. They mentioned several features in that strange context. Thanks! Now it will drive me insane until I find it...LOL
The concours 14 has that secondary balancer, but the ninja is as it always was. It would require a new motor design to add a secondary balancer, and it would be shown on the parts breakdown, and its not.
Heres the 2017: https://www.genuinekawasakiparts.com/oemparts/a/kaw/5aeca8c387a8660ef49ebc9f/balancer
and here's the 2010 z 1000
The article mention things like, "new single shock rear suspension derived from the zx10, new seat, 1043cc engine, LED lighting, secondary balance shaft, 300mm front brakes...."
It was in a context like that. You could see that the lights were a new feature, as was the seat, but the rear suspension and brakes were there all along, as was the engine.
Do you remember where you saw it? I feel like it was just before the bike was released? Late 2016, maybe?