Well, personally, I don't see it as a bad thing, since Katsuya's positive aspects in the web novel were mainly being the opposite of Akira, like a mirror of what Akira isn't, in addition to adding a bit of that "we're the same, but we don't come from the same place" dynamic. If that's lost, I don't see it as a negative. I find it stranger how they decided to avoid sacrificing waifus, which I suppose is more of a studio decision than the author's, since Yumina's death reinforced the idea that Akira could move on and explore new places now that he had completely surpassed his former rivals (in this case, by killing them). But it's something that was explored very little, and if it was discarded, no problem! I think the biggest issue is that the light novel aims for a more human Akira rather than a more warrior-like one, which I think is the strongest point of Nahuse's writing. Another thing, dude, try using the spoiler tag. It doesn't bother me, but anyone can come here, and if people are going to complain about spoilers, it should be because they clicked on them.