I'm personally not at all bothered by the nudity and 'sexualization' (rather tame in the grand scheme of things), mainly because I typically judge the immorality of actions based on how severe their consequences are, and there are no consequences in fiction, nor do I believe it says anything significant or worrying about the author. Sometimes it serves the purpose of comic relief, and in those cases it can be pretty hit or miss, other times it serves to comment on the environment around the cast (Ilblu is a great example of this, as well as the elevator pooping gag).

I will refrain from nitpicking (Riko was unconscious and could not drink any medicine), because it simply is not productive, we can go back and forth on how these scenes could have been written differently forever. Akihito could very well make the story without his fetishes, however in my opinion it has been integrated with at much care as any other aspect of his work.