Eh, I do like Kouya's new design, I don't like Tora's though, for the same reasons, Kouya's original design was very good, so going to a design closer to that is good. But Tora's original design doesn't feel good for me, it's goofy and just strong for the sake of it, for someone who only swims his body should be fit and good-looking, not bara-like. But even so, It's understandable to change the style. Because the old style was very inconsistent, Kouya's design wasn't that good compared to others, and at least in this new closer to the original one, they are kinda looking like all of them are drawn with the same quality control in mind.
I won't come here asking for a re-design again for Torahiko, I do prefer his previous design but then again, I prefer a cast that has the same feel to them rather than a cast where half of the characters looks good and the other half looks bad because of a lack of consistency. As long as the other images in-game such as sex scenes and other scenes feel like they were drawn by the same artist that would be good for me. That's a thing in almost all VN's I play, at least the furry ones: The sprites and the cutscenes appear to be drawn by different people, that's why Kouya looks one way in the sprite and completely different in the scenes on his route on the original Morenatsu. xD
Anyways, I know you don't like it, so just do it like me: Save a print of the sprite you like, and keep it in your heart. If they are saying it's better and easier for them to work with the new spirits, let them do it. I prefer to see this game finished rather than canceled because they need to keep with a level of detail and workload way too big for them to finish this.