You guys are blowing this out of proportion. It will be a good thing to try to introduce a corporate culture where all the products have synergy between them. There will still be a head of Xbox, who will report to the head of hardware. Wasn't Xbox under a "devices" group before?
It's kind of like Apple. They have Jony Ive as head of all hardware/user interface designing (Mac, iDevice, Apple TV), Craig Federighi in charge of OS engineering (OS X and iOS), Dan Riccio in charge of all hardware engineering (Mac, iDevice, Apple TV) and Eddy Cue who is in charge of all services under Apple.
All Apple products have the same overall look and feel as they're all developed by the same teams. In that sense, we'd have someone responsible for overseeing all hardware efforts, to bring the devices together. It's to leverage Microsoft to be its best.
Microsoft and Sony are huge corporations with a huge portfolio of products, and bringing synergy between them is a good thing. In fact Kaz said he wants to bring synergy between other Sony divisions and PlayStation, and having that Sony Pictures guy on stage at E3 is only the beginning.