Given that the RFC input format is XML, any editor that doesn’t operate on that XML is always going to put you at a disadvantage. It would be nice if there were a standard format we could use, but I don’t know of one that would work. Using markdown, or Latex, or whatever, just adds one more layer of translation you have to deal with later. I occasionally try to use markdown, but keep reverting back to XML because it’s just one less step.