Thinking about this a bit more. I kind of like the fact that currently, the master branch has a single thread. I realize that merge commits that are made with merge -s ours don't represent "real" dependencies, but that's not obvious unless you dig into the commits and see that the merge has no diff. So I'm inclined to drop back to the "merge-with-the-release-branch-when-its-created" strategy. I'd really like to hear from others, though. @samth ? @mflatt ?
This should probably be a separate topic...