It follows a typical weak to strong structured plot, you have a protagonist who due to forces of circumstances and coincidence gains the power of his dreams, that power being, be a samurai, albeit a not full-pledged one.
After that, with the guidance of his master, he'll meet a colourful cast of characters who'll change his life for better or worse, villains to fight with, and an overarching plot that involves multiple planets and possibly an intergalactic conflict.
One of it's main problems is that the action itself is a little too hard to follow, the samurai powers haven't really been explained all that well, also the art is too busy and unfocused, which is definitely a no-no in a battle shounen.
Again, it's not inherently bad, it's just painfully average, it's like Kishimoto was in a time capsule and left 20 years later thinking that what worked in 1999 would work again in 2019, with a fresh colour of paint. Araki, for example, is an author that reinvents itself in each and every JoJo arc, it's a shame that Kishimoto can't do the same.
Overall, while Samurai 8 will probably be a moderate success due to Kishimoto name attached to it, it'll be a far cry of what Naruto achived due to it's dated design.