I'm thinking about a historical game were every game and sequel follows a single-family line though out the generation. One game you play one guy and the next a time skip them you follow his children. It starts following a family in the Hunter gathering age and eventually lead to the far-future...
Better picture or scene setup, games are a visual medium. So you need to think of how you present the scene to make it look good. Like artistic composition can make a mediocre scene into a amazing scene, even if it a scene that don't really mater.
If it short then you don't really need one sense you can just replay it and finish it quick. If it long then you may need help trying to get certain paths in the story.
You can never have too much, why not have a army that your harem but in seriousness in a story you would need to be able to have time to showcase all these characters and have them shine. If it too much then people may feel like you are not spending enough time with certain characters they like...
Daz seams to be a good choice, their lots of models and assets for it. Sadly some aspects of the program seams very "Primitive" or archaic. I heard some people used blender, it more advanced but I guess it way fewer people used it in regards to Renpy games.