Your system will end up with mountains in the middle of continents instead of mostly on the rim. Although they are tile-based, you migth want to look at the various Civ IV map scripts, they are in python and the tiles tend to be an after-effect thing since several models don't really care about them (check PerfectWorld in particular:
http://forums.civfanatics.com/showthread.php?t=310891 )