Documentation. A subject that is as important as the code, maybe more. We are internally always debating what does an user should known by default, and how. Both matters and depends of the target (noob, average, expert) or which approach first (kv based or python based). I personally don't know how to write a good documentation, except if it's just API documentation. But in that case, API is just not sufficient, as concept need to be explain as well. We have actually one big big big contributor named ZenCode who work behind the scene on the documentation, and constantly fixing our mistake / wording. I ear you loud and clear, wish to have a better programming guide / module documentation as well.

About ListView... Let's say it's one of the Kivy widget that doesn't fit to the Kivy logic at all. Historically, i started a POC about it, then a contributor take it and worked a lot to have something that works for any sort of situations. And he tend up to something that cover lot of cases, but still bugs, and not easy to get it. Not to mention issue with performance. That's why i rebooted the ListView from scratch, and named it RecycleView (like RecycledView from android): https://github.com/kivy-garden/garden.recycleview

The visual design was taken from Meego / Android in the old days. We might be able to refresh the theme one day, if we have somebody that can contribute to it (i mean a real designer, not a coder). I rarely use the default theme, always extend a widget to put the designer visuals i got on customers projects.