Make the characters grow and change just like in real life. In fact from my estimates it would take 100 years to get bored of Fallout 3. After you implement my amazing ideas I would not be surprised if Fallout 3 becomes game of the year again and may even beat Fallout 4. WE will let the next 100 years decide.
You need to understand that this game is about the characters. By characters I mean all the creatures and races. imagine if npcs did more than they did. realistic eh? all you need to know to begin implementing my idea is to recognize fallout 3 has room for this improvement.
if enough people post inthis thread demonstrating they would like me to make my own mod, then i will do so.