When it's ready ;)

To actually answer your question, nobody publicly knows - at least that I'm aware of. Even Steemit, Inc. might not have a date set yet. It is hard to predict how long all the features will take to add, as well as what the communities expectations are going to be once new things get added - what else will they want? For example, recruitment guilds were probably not even part of the picture 2-3 months ago, but now they are going to be one of the big development efforts over the next several months.

As a complete guess based on my own development career (I have no official info to back this up with) I would estimate about 2 years for the current project to reach what would be considered a 'non-beta' stage.