Inclusions are absolutely stellar, I know some people dismiss Asciidoctor because it feels neither here not there kinda lang. It amazes me how pliable the tool actually is (for Rubyist off course), there are some things there that would make org-mode aficionados and LaTeX die-harts envy.
I feels and works more like a real programming language while still having uncluttered syntax, you have variables, cases, etc. You can make your own plugins relatively easy. It's not in your way when you are writing.