XML is completely unneeded at this point. Your map should explain, without code, how to play on it, what bonuses it should have, and what continents/symbols mean what. XML should be reserved for when proof of concept is made and interest is WELL-established.
I personally would love to immediately XML code the maps I'm working on (programmer at heart), but they're under revision on a consistent basis. All of them have had border, bonus, and continent changes in some form or another. In the XML that would require rewrites of entire sections, a big huge waste of time for a mapmaker. Keep things in those terms.