Oblivion does look breathtaking. And believe it or not, I'm playing Morrowind and enjoying it.
I've installed several mods, but most of them just tweak a few rules, fix dialogue, and improve textures.
What's surprising me is how fast the game loads and runs on maximum graphics. I wouldn't want Fallout to be like Morrowind, but Bethseda did do a few things right with Morrowind. So long as Fallout doesn't have this "increase skills through repetition" thing going, they might make a decent Fallout game.
At the very least, I expect it to be visually stunning.