I really like how this came out, personally. Ruko's voice suits this song well and your tuning gives his voice a more emotional tone, in my opinion. I especially like the soft parts. I'm trying to figure out what it is that you might not like about your tuning and the only thing I can come up with is the fact that the notes sound slightly jarring/disconnected in places, almost like a CV bank (but nowhere near that noticeable). That's probably less due to your tuning and more due to Ruko's voicebank having really strongly pronounced consonants, but if you want your tuning to smooth that sort of thing over a bit, it might help to take it easy with the swooping pitchbends at the beginning of notes. They sound good, but I think too many of them can emphasize that disconnected feeling.
But I'm certainly no expert at tuning, so don't put too much stock in what I have to say about it. ^^'