Randomize the maps would mean randomize also a lot of quests... And I'm sure that will not happen
Do you know how hard would be randomize the quests? You can set to appear random creatures, but random quests... The game would need a huge database of missions, because of that, it's easier to place a point of decision in some moment of the main quest, so that you could choose, for example, the good path or the evil path of the game, and consequently change some secundary quests.