it's not that he can't complete a swing, but that he can't complete it in the correct FORM. Specifically, it's that
his senses are so overdeveloped that, when he swings a sword, he's constantly making minor corrections/overcorrections mid swing.
I checked out the translation of the WN, one of the translators actually has the whole thing done with no paywall but they were using mtl. It still reads just fine, it's just a lot of uncertainty with genders. Anyway, it was actually pretty good. Compared to others, it takes its characters and subjects a lot more seriously than I expected. It makes some of the events much darker or more serious than you would expect. The biggest example being the demon queen of love's attack.
You would think the "succubus spreads mist that makes everyone blindly horny would be played for eroticism but during the event it's mostly used to force them all to separate and show their own growth. Most of the discussion is on the traumatic aftermath. Husbands and wives not sure what to do now that they don't know if they impregnated or got impregnated by some random stranger, 10% of the students drop out due to trauma with an uncomfortable portion of them also being due to teenage pregnancy, the worries over the number of abandoned or orphaned children that will make up the coming generation. That's what the story focuses on. Well, yeah. There's also a lot of development for all of the characters and their relationships rather than it just being 'mc and harem = good, everyone else = bad'. Honestly, the fact that there's other prominent male characters and they can have their own romances with prominent female characters is better than most.
