I don't think that the lack of genitalia is problematic in and of itself. Most people including I probably don't care about that. The reason I find it discouraging is that the lack of genitalia might serve as a clue, but certainly not proof, that other aspects of the game will also be kidified. For example, if an improperly fed lion escapes into a gazelle enclosure, what happens then? Genitalia no, but realistic predator prey interaction yes? Seems unlikely to me. This would somewhat destroy my immersion, as I would realize that I am not managing a properly simulated lion where I need to make sure to keep safety in check, but rather an icon with beautiful animations where nothing dangerous can happen apart from some dissatisfied visitors. But that is just my opinion.