It looks neat and all, but the Hexagon has existed for a while in a number of phones and I've seen pretty minimal usage of it. Would more ARM cores be a better use of die space? Also, why not implement the video codecs on it and drop the fixed function hardware?
HVX is designed to handle significant compute workloads for image processing applications such as virtual reality, augmented reality, image processing, video processing, and computer vision. This means that tasks that might otherwise be running on a relatively power hungry CPU or GPU can run a comparatively efficient DSP instead
Also looks like they posted some actual benchmarks. The numbers do look pretty impressive. I'd also like to see some results compared to shaders - some of them (histogram) are not a very good fit, but many of the other convolutions would be.