I think firstly, unlike Spirit Circle, or even World End Solte, this manga starts quite slow and really takes its time to get going, arguably longer than Biscuit Hammar. This is a series that really relies on its characters to drive its story, but it does take its sweet time getting to explain its character's core motivation and complexities. I really do not blame readers for dropping this early as the characters and setting can seem... quite generic in the beginning. I myself, tried to read this manga years ago, and dropped it early because it did not compel me much.
Sengoku Youko is also structurally messy. Plot points weave in and out of this long journey spanning 8 years and longer, and some scenarios are thrown into the mix without sufficient narrative planting. This can make certain plot points feel rather... convenient and sudden. Not to mention it did the whole thing of throwing in a whole new group of antagonists and a central conflict (that barely has anything to do with the inital conflict) about 30 chapters in, and the role they play is strangely significant and insignifcant at the same time. I really do admire the attempt to play with story structure - splitting the story into 2 parts and changing the central protagonist. But, while this was incredibly exciting to read in the beginning because it was difficult to predict what might happen next, I felt all this structure served to really do was to underdevelop some of its crucial characters and preceeding plot points (especially perceivable at the end) for the sake of developing its new main characters and their journey.
Still, Mizukami Satoshi's mind works in grand, mysterious ways and when this manga hits its highs, it really does hit highs. Shinsuke's character development was excellently constructed and he was consistently one of the best characters in the series. He had a very intriguing moral development, and though his role as 'mentor' later often sidetracked his own development as a character, it was still engaging and emotionally touching to see his whole journey. I also liked the spiritual themes that the manga tackled - interpreting mental state and the inner self in a very mature way. I also enjoyed its rather inventive ways of solving conflicts (though in the grand scheme, can feel a little unsatisfying).
Overall, I think that Sengoku Youko is an intriguing and fine manga that plays and experiments with new ideas and storytelling forms within the cliches of its demographic, but I think this is not an experiment that fully succeeded. For better or for worse, this story could read as a breath of fresh air with its many refreshing subversions to battle tropes, but also a lengthy mess that never really felt like it had a clear structure or a conclusive end goal. I would highly recommend checking our Lucifer and the Biscuit Hammar or Spirit Circle for projects that captures Mizukami Satoshi's eccentric writing and storytelling style within a more cohesive structure and story.
