At that point it's a matter of updating a few build scripts to pass AsciiDoc files to pandoc instead of Markdown. I wouldn't say starting with AsciiDoc would have been better or worse, just different. Starting with Microsoft Word would have been worse.
The brunt of transcoding from Markdown to AsciiDoc can be accomplished in a single line, something like:
AsciiDoc is a superset of Markdown, so pandoc should be able to do a nearly flawless job at converting:https://asciidoctor.org/docs/asciidoc-vs-markdown/
At that point it's a matter of updating a few build scripts to pass AsciiDoc files to pandoc instead of Markdown. I wouldn't say starting with AsciiDoc would have been better or worse, just different. Starting with Microsoft Word would have been worse.