Koei Tecmo has been very active in 2016, and it appears that they have some quite beefy plans for 2017 as well, as mentioned by some of the publisher's Producers on 4Gamer's traditional year end mass interview.

President and Producer Hisashi Koinuma talked about plans to release many console games, including the support of new hardware.

This year we will release numerous titles for home consoles, and will also challenge new hardware and mobile titles. Everyone, thank you on behalf of Koei Tecmo games. Also, even if I'm the president, I'll still continue to do some development.

On the other hand, Toukiden 2 Director Kazutoshi Sekiguchi talked about the future of the series, but he also would like to try something different.

Currently, the "Toukiden" development team is at a stage where long-term sabbaticals have been settled, and many ideas are being developed. I think in 2017 we'll be able to show the development for the next. I personally think I'd like to challenge new titles aside from that.

Producer Takashi Morinaka also teased a new Toukiden reveal coming in 2017.

We were able to released Toukiden 2, the latest game of the Toukiden series, in 2016. I'd like to thank everyone who played for the support! Also, in 2017 we'd like to continue by delivering a new evolution of the Toukiden series, so look forward to it.

Koei Tecmo already announced that it will support Nintendo's Switch, so that's probably what Koinuma-san is talking about, even if he did not mention the new console directly. That said, it'll be interesting to see if the new Toukiden evolution will be an entirely new game  or an enhancement of Toukiden 2 like Toukiden Kiwami. We'll have to wait and see on that.