Mart's Mutant Mod for Fallout 3 adds many new enemies, including well-known enemies from the first games in the series and an overall improved AI. With the help of this mod, monsters can now fight each other, while Raiders can equip better armor and weapons, and loot dead NPCs, which makes them much more dangerous in combat.
This is probably the only feature that Bethesda got right this time. The AI in the new game behaves much better in comparison to Fallout 3, where enemies were simply jumping out of their hideouts. But a lot of fans are still hoping for an AI mod that will influence both enemies and a companion in some unusual ways. Let’s wait and see what the community will come up with.