More information is coming regarding what is going to be happening with Games Workshop's Warhammer 40k and Fantasy, including mention of Adeptas Sororitas. This gives us a short view of what we will be seeing with the armies that still have softcover codices floating around. After Grey Knights, there just wont be many left (3).
Please remember that these are rumors.
via Voice of the Chaos Gods on Faeit 212
Dark Eldar will most probably come next. The four codices for replace the last softcovers are all complete. Theoretically, GW can publish them all in 2014.
Sororitas were written by phil kelly already in 2013.
Problems with the molds prevent the publication.
Necrons and Dark Eldar are getting for their codex publications only few new Models.
Both systems have only three regular rule writer. The writers for 40k are Robin Cruddace & Simon Grant. Fantasy has Phil Kelly & Jeremy Vetock. Jervis Johnson is in both games the senior writer.