This is good news. For many years I have been following Gimp with the hope it will introduce high color depth. Actually, the last time around a year or two ago I gave up hoping. To me 8 bit color depth is unacceptable. Why would someone work on building a Ferrari and put in a 5hp steam engine? I just couldn't get it. Now I'm glad to finally see a change.
You mentioned AMD graphics support for OpenCL, but what about Nvidia OpenCL support in their closed-source drivers? As far as I understand, Nvidia supports OpenCL in its drivers since the 280.13 release. Moreover, they have SDK sample codes and CUDO open source code for developers, too.
Any reason for not mentioning Nvidia? Or any reason why Gimp wouldn't work with Nvidia cards and drivers?