I was open to criticism of Sayooshi as I am in agreement that it isn't perfect. But I couldn't find myself agreeing with any of your criticisms. It seems more that you dislike it because its popular in the small, but vocal crowd of English speakers who read retro Japanese VNs. And I can relate to that sentiment, if Doki Doki and Fate Stay Night for example weren't so popular I wouldn't mind them as much either. There is something particularly frustrating about disliking something that everyone else seems to adore, so I sympathize with you in that regard.
What I will say, is that I think the reason Sayooshi gets adored so much (by me included) is because genuine denpa isn't a very popular genre. Sure you have VNs like Suba Hibi and others that have denpa segments, but its rare to get a VN where the denpa is the primary focus. And for those who love that genre, Sayooshi scratches in all the right places (for most of us at least).