To me it’s a step up from The Book of Souls, particularly in the guitar department, but there are definitely some clarity issues.
The thing that I think people are missing the most is that the production varies quite a bit from song to song. Senjutsu is one of their more uneven offerings in that regard. I’ve noticed in particular that the three songs Adrian and Bruce wrote sound marginally better than the rest of the album, particularly Writing on the Wall (prob the best sounding song on the album). Some of that is also arrangement. There’s a lot more space in those three songs for the instruments to breathe. Bruce spends a lot of time in his lower register during Harris’ songs, which makes it easier to get lost in the mix. On the songs he wrote, the vocal parts are naturally better arranged. Guitar parts don’t overpower the vocals when Bruce is singing in H’s songs. That kind of thing. Still, Writing on the Wall, Darkest Hour, Days of Future Past all sound like a notable enough improvement that it makes me wonder if H (or even Bruce) asked for their songs to be remixed at one point (probably early on, like pre-pandemic). Usually if there’s a production oddity on a Maiden album (vocals too low, guitars sound thin, etc) it’s true for the entire album.
With that being said, by far the worst sounding track imo is the title track. It’s so muddy and seems really mid heavy. Some of the vocal overdubs don’t sound tight. It feels like demo quality at times. Keeping in mind my comments about Adrian’s other songs, I am surprised that this one passed the quality control filter, even for Maiden’s usual standards. I strongly believe that the poor audio quality of this song is coloring people’s impression of the entire album. Because the rest does sound fine for the most part IMO.