I'm tempted to have a go at making a map, I've made fantasy maps before (e.g. Montour
). I'm also tempted to combine information into a background book, create some standard material for each faction - a representative symbol, colour, language, etc.
Why? Well, form my experience with the Hero System and other roleplaying games that are generic, customisable and without settings - I've found players generally lack the time or motivation to create their own settings. By far, new players to the game prefer existing settings, and to create stories that add to it, rather than having to think of everything before they even get started.
Only particular kinds of people enjoy world design - and it is a minority of those that play the game.
Besides, there's also a question of authority here. If no one has done it, then the first good one is likely to be referenced by later players. I'd rather the "official" styles of the factions were not left to chance of whomever has a whim at any time in the future. Consistency really helps.