I can see the appeal, but it's a theme park simulator as a much as a dinosaur behaviour simulator. Wouldn't it get really irritating if the game constantly cycles through two different modes of play, where one of the modes is mostly watching people and dinosaurs sleep? Yes, you could add gameplay that works during the night, but I think it would be a slightly different sort of gameplay and might frustrate if you just want to get on with building things.
Also, as it stands the dinosaurs don't even sleep. I would love to see a gameplay mechanic where different times of day affect the goings on in the park. For example, at night the guests either depart the island or go inside their hotels (otherwise, honestly, whats the point of having hotels) to sleep. The dinosaurs also start to exhibit different behaviours. Perhaps some the carnivores become more active and there is an increased probability of breakouts etc.
This would add so much immersion and I'm a little bit surprised this wasn't thought of at the very start of development. I've said many times in these forums that nighttime is a fundamentally important time for the JP aesthetic and it really deserves to be treated well.
I have some nit-picks as well regarding the treatment of nighttime. To me it doesn't seem dark enough (from what I've seen) and there appears to be a complete lack of any floodlights which in my opinion is a travesty.