Vlad: I'm sure you know about Markdown. Markdown is a light weight plain text formatting syntax. There a many flavors of Markdown available; so many it is hard to track or figure out which to use. Pandoc markdown is as good as any and designed to work with Pandoc.
1. Can Markdown support be added to AMN. A useful (?) blog post: https://www.ossblog.org/markdown-editors/. There are plenty of other resources.
I used an early version of Haroopad; looks like feature set greatly enhanced. Haroopad was, when I used it, hard to uninstall. I could never get the icon out of the program list in Control panel & spell check was missing. It was indeed a great editor; but I needed spell check.
2. Can Pandoc http://Pandoc.org be added or by some "magic" access to Pandoc provided? Either way is probably a monster task; adding Pandoc is a monster for sure. I might be the only one interested but this would provide a huge amount of flexibility. Also might make for a ton of bloat, something I know you are trying to avoid.
Just some thoughts.
Thanks
John