1st: Please post in the correct forum This makes our volunteer moderator lives a lot easier and it isn’t rocket science after all. I moved this post from Forum News, FAQ and Feedback (where it clearly didn’t belong) to the DJ Booth.
On-topic: I think the question/suggestion was asked/made very recently and even answered. We wouldn’t really know as forum moderators as we are not prone to the schedule the main site operates on, including release dates and what’s in the pipeline by way of new stuff.
It does seem reasonable to assume that the Ninja courses over on the main site on Serato, Traktor and VDJ will get a RekordBox DJ sibling sometime in the near future. But that is purely an assumption on my end.