On one level, akin to Trash, this wouldn't be too bad an idea. In a Road Warrior fashion, this would be great with raiders, concerns of fresh water, food, weapons/armor, fuel (a big thing in the Fallout Universe, because it's the cause of the war that led to things glowing), and people.
This would be good completely separate from the other Fallouts and not interfering with the storylines or tying into them outside of some minor details.
There is an issue over where to get supermutants and that sort of thing from others, and naturally the "wild critter" side would be a touch different and hard to do. Balance for the supermutants would be easy to do, and a challenge, as they would have to subdue people instead of killing them, for their main supply of troops.
An interesting idea and does have merits, but only if done well and doesn't interfere too much. Mainly because it *may* fit the setting, as would have FOT if it was done substantially more competently.
I'm also going to move this to the "General Fallout Discussion", as it would be more relevent there instead of for a Fallout 3. A side note, please refrain from using "u", as there might be a script addition that might make it a bit more...educational. ;D