In an interview with IGN right before todays announcement Toshihiro Nagoshi confirmed that going forward the mainline Yakuza games will be an RPG. This confirms what many already speculated that there’ll be more yakuza games and Judgment will likely live on as it’s own series past these two titles.

“The Yakuza series has been transformed into a turn-based RPG. On the other hand, over the years, Ryu ga Gotoku Studio has accumulated resources and know-how of making flashy and exhilarating action games that are effortless to enjoy. We decided that we should let our signature action gameplay live on through Lost Judgment.”

[source]