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.