Actually, I already use Haroopad with Pandoc, there is not a lot of problem of syntax compatibility for now.

The thing that could be great is to be able to open a console which run/execute a command on the current file from Haroopad.
We could save our created commands and they would be accessible from the menu, and we could also link those command to a keyboard shortcut like in Notepad++. That we could link Haroopad to anything basically.

Then, we could create a command: "pandoc current_file output.docx" and linked it to a keyboard shortcut.