In order to celebrate 15 years of Warriors (or Musou) titles in 2015 - including Samurai Warriors, Hyrule Warriors, One Piece: Pirate Warriors, Fist of the North Star: Ken's Rage and Warriors Orochi (and many others) - publisher Koei Tecmo said that they'd have a pretty cool announcement for fans of the franchise.
Now the year has passed, and that announcement obviously hasn't happened, however in an article in the newest issue of Famitsu (translated by Gematsu), developer Omega Force apologised for the delay, and says that we are to expect the major announcement sometime this year instead:
"Last year, we welcomed the 15th anniversary of the Dynasty Warriors series, and we were not able to deliver the news fans were expecting. For that, we are very sorry. This year, we're preparing to be able to make a big announcement, so please look forward to it."