Post your mapmaking strategy here. I use Civilization IV. The base game contains multiple map scripts like 'archipelago' or 'highlands,' but despite being balanced for gameplay they're horrible at producing realistic terrain. What you need to do is to get a player-made map script called 'perfectworld.' It's available as a standalone download, but I'd recommend using the mod Rise of Mankind: A New Dawn instead. This mod includes perfectworld, and also adds marsh terrain. You want swamps in your setting, don't you? I can't speak for any other game, I'm afraid - but perfectworld is a reliable choice.