Aside from completely redesigning the world and side quests, there’s nothing they can tack on to the game as is that would make it worth playing again. It’s boring and missing the one thing they actually did pretty well in everything else: environmental storytelling. You can’t exactly use environmental story-telling when your game’s environment is mostly randomly generated; which is what all the areas outside the main cities are. Randomly generated set-pieces that are scattered around an otherwise empty planet.