This is open source after all so saying "feature x will be released when its ready" is perfectly acceptable
Sooner or later we will publish something like a roadmap and we will probably start in a form without strict deadlines and may move to deadline estimates later.
The reason why we are reluctant to do it right now is simply because the team agrees to undercommit and to overdeliver. We are - as probably most of you too - fed up with "plans", "intentions" and announcements that may turn up to be vaporware.
So for the time being, we would like to limit our announcements for the situation when we have something that is ready/available at the time of the announcement.
We believe, in time, this will be the best image our group can build, because always when you see a PoC announcement, you know there is "one more thing".
For those who are impatient, or would like to monitor the development process more closely, we set up a Twitter account where we intend to publish the smaller things like "New feature here and there".
https://twitter.com/PoC_Consortium