It would be nice if there was a docker image or a VM new developers could download, and which had a batteries-included Lisp/Scheme development environment with emacs/vim prettied up and having all the bells and whistles, so they could just start hacking away instead of spending days or weeks learning, setting up, and tweaking their editors and downloading and installing tons of libraries and plugins.
https://shinmera.github.io/portacle/ <-- it needs a bit more testing so the scary warning message at the top of the page will go away, but it's impressive already IMO.