I am sure Kabaneri will be popular, because the production values seem slick and the Araki/Sawano duo can provide plenty of inherent blockbuster appeal, but it doesn't really look too interesting to me. Evidently, Tetsuro Araki has plenty of visual polish and technical skill, yet I still think most of his projects tend to feel rather empty and /or nihilistic at their core, beneath all the bombast and loudness. Even when it comes to adaptations of existing source material, I think he overly emphasizes the more superficially shocking and cynical aspects of each work.
This time around they're obviously going to be following the Attack on Titan formula in almost everything except setting. Beyond that, all these trailers just give me the impression of an ultra-violent 1980s OVA with lots of gore, fanservice, zombies, samurai/ninja action and so on, where increasingly horrible things will happen to keep the story moving.