I dont think its cause they like incest so much I think its because people love the characters so much or at least its the case for me
That is valid of course. Understandably so.
I would love to have a "deeper" relationship between MC and Azel as she is a wonderful woman and stunning.
But its simple, BD does not want to make it happen, it is not necessary for the story to be believable or good,it would only feed the fetish of some ( Ok, many.. Pron site here after all ) but still.
Not going to happen and I do not only understand this decision but also respect it.
IF someone wants to make it happen, them is free to mod the everloving s..t out of the game. Would respect the skill and dedication of that person. Dunno if I would play that mod, but hey skill is skill.
At least it would be time better spent doing the mod than some people bitching about it ( Not talking about you of course alpha )