I think it's fine to voice your concerns and criticisms, but some people are acting as if the dev has committed daylight robbery or something.
I don't mind the pacing since it's not often you see a game build up this much. I can list dozens of other games that get to the sex quickly, but there are few like this.
I'd maybe be harsher towards the dev if it was still not finished after like 5 years, but at the end of the day, not all games are meant to cater to everyone. If I made a game, and some passionate fan criticized it for not having pegging in it, I'd appreciate their passion, but since I ultimately don't enjoy that fetish, I wouldn't bother with it. Likewise, the dev's already made it clear they value the slow corruption of the fmc, so to expect otherwise would be a futile effort.
Could they communicate better and have larger updates? Definitely, but I'm personally not gonna hold it against them too much since this game's only been out for a bit under a year and is already one of the better games on this site.
FWIW, the feature I want most implemented is the ability to rename some of the other male characters. It feels insanely awkward to play if you know someone irl with the same names as the ingame characters.