I think this is great, but at the same time, auto-installing homebrew ought to be an option (perhaps enabled by default) when installing the “XCode command line tools”. Better yet, offer a “developer setup” app that sets up the command line tools, homebrew, iTerm2, updated bash/zsh, and more. Apple would do best to pave the cow paths developers have already worn into macOS, especially when it comes to command line ut…
It sounds like what you're really asking for is something like Ninite for mac, which I think frankly is safer to stay as a 3rd party thing, rather than Apple getting super-involved in choices that are going to be very user taste specific.