It doesn't look like this is going to get committed this release cycle. I understand more feedback could be valuable, especially on the overall design, but as this is the last commitfest of the release we should focus on other patches for now and spend that time in the next release cycle.
I'm going to bump this one now as Waiting on Author for the design documentation Robert asks for and probably a plan for how to separate that design into multiple separable features as Andres suggested. I'm still hopeful we get to advance this early in 16 because I think everyone agrees the feature would be great.