Snowman75
I think I understand your point and that's something you can read alot in other games, which focus mainly on story than being a fap-fest. The reason for this is the nature of the releases of these AVNs. You get an update each 1 or 2 months and because of this the story can only progress in small steps. Compared to a movie or a book, where we have access to the whole story at once.
The dev/author has the plan of the story outlined in front of him and knows some of these questions are already answered, but it will take 1,2 or even mroe updates until the fans reach this point of the story. Many answers to questions or speculations on here are going to be revealed at a later point in the story by choice of the author. You have to build a arc of suspense to keep the audience listening to your story, but this doesn't work as we get only a small part of the story each time we get an update. The final product will maybe a story which takes us 5-10 hours (pure speculation just to have some numbers^^) to enjoy, but if we are here for every update on release we will follow the same story over a timespan of maybe 2 years (again pure specualtion).
There are many movies were you see a scene in the beginning which makes no sense with the available information at this point, but there will be a time in this movie, maybe be somwhere in the middle or sometimes you even have to wait for the great finale to understand everything.
Coming back to Rebirth I think the story behind the woman who made the MC is something the author will tell us, but he decided to do this at a later point and I'm totally fine with that. About the MC and his reactions to some stuff happening around him (thrall, visions, etc.) I think it's his personality to observe new things happening around him for some time before he starts dealing with it in and acting on it. But thats just the impression I got from the MC so far.
I wouldn't call it a weakness of the game/story, more a problem of the method we experiencing it