I think that it would be
nice (good, pleasant) to have a more general roadmap, letting users know what developers are working on (or not), even if the feature has no release date... (or something like "planned for the future") and if one feature has an expected release date (or month, or quarter, or year), it could be easily stated there, and people will be happy. And if a date changes, or becomes undetermined, it will be perfectly understandable.
It is not about promises to be maintained, it is some kind of communication, letting people know what's going on in the near or distant future, or never, without the need to look at (and understand) git commits... something like
http://www.spice-space.org/features.html
I like nice people more ;-)
Marco