We haven't even seen the Creation engine, it is supposedly just Gamebryo 2.0, so I don't expect much, it isnt some sort of super savior that will improve the games 100 fold.
People are treating the Creation engine like some sort of technological panacea, when it isn't.
Graphically, it won't be cutting edge, no.
But for a game like Fallout, it WILL be incredible.
It will allow Bethesda to bring the wasteland to life, making it more dynamic, bringing back random encounters, weather, that sort of thing. It's going to make FO4 an incredibly dynamic game world to explore, while improving combat and the like. People will look and move like people, and to top it off, it while improve the graphics.
It's a huge step up for the series.