The last remaining German website I read reached out to Microsoft about the question we've all been wondering about.
According to MS the 10% were a very conservative estimate and Kinect doesn't use that much power of the system. X1 will have the 10% boost of performance without developers having to turn off Kinect functionality. MS wouldn't go into detail but said that at least it will be able to still receive and process voice commands.
The site is a very respected, independent and highly frequented computer magazine so please don't doubt this article.
http://www.computerbase.de/2014-06/kinect-funktionen-neues-sdk-xbox-one-bleiben/
My take on this is that it was kinda expected. Voice commands probably won't take away from the GPU resources. Full on Kinect games probably won't have this benefit but who cares about graphics for those anyway.
If you demand respect or gratitude for your volunteer work, you're doing volunteering wrong.
