They certainly had an actual timeline for 5G, but once that got scuttled, I understand why they decided wait until after whatever Death Metal accomplishes in terms of their overall continuity to publish that timeline since it won't be used any longer. If the rumors are correct, and I believe they mostly are, then a definitive timeline as we got during Zero Hour would be somewhat redundant because the DCU will using a more malleable continuity moving forward.
I think we'll get a broad strokes retelling of the overall history of the various superhero eras, but a year by year timeline nailing specific characters and events down to stated numbers of years ago would be counterproductive to what they're trying to accomplish.
Hypertime appears to be the plan, with one main timeline that is constantly getting tweaked as alternate hypertime streams split off while others join the main river that is the primary DCU. Once again, Grant Morrison was decades ahead of the game and people are just catching up to him now.