I think the next fallout should look like Vampire- the masquearade, except the same play style. It would be pritty cool to be able to see everything that up close.
While other views may offer more eye-candy, the FO games have never been about graphics and I doubt that will change when FO3 comes out. I personally think the 3/4 isometric view used now is the best for RPGs, anyway.
now that i think about it you guys are right, although a nother idea would be to make more area, instead of the same old towns, like the riuns of new york or you are able to travel around the world, useing ships or boats and such.