By Hundred Years War, I assume you mean the period circa 1337 to 1453. A lot changed in this period, for example the Kings of England quartered their arms with those of France when they claimed the French Crown.
It’s really anachronistic to describe these powers as “nations” at this time, as they were really more like extensions of Royal Courts, which frequently cut across ethnic and language boundaries.
I appreciate the need for game balance in map design, but my interest in history and board games go hand in hand, and for me as primarily a historian there should always be a way to accommodate historical accuracy into the game without ending up playing on a chessboard. I live in Northumbria, and the idea of it bordering Champagne to me is rather like Iowa bordering Japan.
Attached an example of the heraldic flags I draw relevant to the HYW, though you’ll be aware that WOE is set in a rather earlier period.
For me the depiction of this era as an elaborate Risk variant misses out the most interesting element of medieval politics - you couldn’t just walk into a neighbour’s territory and take it over by force. There had to be some kind of legal claim, usually one based on blood, i.e. hereditary descent. This is what my Warriors of the Roses system does; it provides a justification for violence. A European version would be possible; the nearest I’ve seen to this is Blood Royal, but that involved too much paperwork.
http://www.boardgamegeek.com/boardgame/248/blood-royale
My system tracks the dynastic side of things purely with cards.
