I've opened #9602 to remove all coin age priority functionality from the codebase.

I think this has been discussed many times and hopefully it will not be the subject of another lengthy discussion, but just in case, I've opened this issue so any discussion not related to the technical merits of the implementation can happen here and the PR itself can remain free for discussion of the actual code.

This is targeted for 0.15, and shouldn't be merged until we ship 0.14, but it came up again recently and so I figured I might as well post the PR. Also in the event that we feel anything needs to be pre-announced with the 0.14 release this will give us a chance to think about that, although I don't think there is anything pressing.