Actually, if you keep up with the forums this is a very high priority. Mail is top priority, AH (or some type of market) is just a bit below guilds (maybe not how I would prioritize, but close enough )
They are actively developing these features. As HCS has said many times, the content team and the technical team are separate. The content team is working on new content, this has nothing to do with and no impact on the technical development of these new features.
But these present new challenges. It's the first in-game features that require realtime cross-server coordination. They must be incredibly secure, above and beyond most other features. Full featured enough to satisfy but without bloating the game.
In summary, we will see these features, and they are a priority. But given the complexity only HCS could venture a 'when', and at best it would be approximate.