I love Zenda's route and feel like she is a great example of how well you two work together. She is funny, smart, has her own emotional issues she is working through, is madly in love with the MC. I find her route to be perfect or as near perfect as anyone can expect. I do agree it feels like she is in a different world than anyone else in the MC's life, she doesn't interact with anyone else. However, the same can be said of Val. She doesn't really interact with anyone else. She also is a well thought out and interesting character. She and Zenda are tied for tops in my opinion. I look forward to seeing how each of their endings go.
I'm not into the Harem route. It's just not my thing. I've played a bit of it and I don't find it as satisfying. Mora is the only other character I like and that's because she's a redheaded gamer geek. If she was a bit older I'd probably enjoy her route as much as I enjoy Val and Zenda. Just feels like there is less content for Mora if the player isn't playing the Harem route. Don't know if that is accurate.
Anyway, you two have made a brilliant game so far, all of my misgivings are gone at this point. I just hope you can stick the landing.