There are also smaller Quick Setting buttons that always appear at the top of the notification shade, similar to what is found on Samsung TouchWiz and LG’s Android UI, but Google’s implementation takes up a lot less space.
You mean that thing that Cyanogenmod had for years now? GGWP Google. Same thing for "more extensive QuickSettings customization", CM allows you to add pretty much every toggle-able setting whereas stock Android is crippled to only allow a few (if your manufacturer's ROM even allows changing them... my Moto X Style, for example, has it hidden in developers options, while Moto G 1st gen. doesn't have it at all) Why is Google hoarding all these easy-to-implement customization options away for years before giving up to the demand?