I agree that an RT/FP version of FO1/FO2 would be totally different games - but if the story and writing in those games is so absolutely stellar (and I agree with that) why not keep them? To expand on what one of the "NO" camp said earlier in this thread - the original games were good despite their graphics but not because of them.
I would say that, for me at least, I look at videogames as an art form - just a different medium of storytelling. Now, the quality of said storytelling is often debatable (I may enjoy Quake or Tetris, but I don't usually play them for the story.) But like any medium, the purpose can be simply for entertainment. Like a big action movie, for example.
Now, I say that because in art, each element adds up to a greater whole (this is called gestalt in art circles.) Change one element, and it's something else entirely. The brush strokes, composition, or the use of color, is just as important to the work as what it is that you're painting.
If you take Fallout 1 as an example, it's made up of the combat system, the dialogue, the story, the character sheet, the way in which you approach the game (top-down or first-person, whether you point-and-click or control directly with the keyboard,) and so forth. Each of those is integral to the whole of the work, which is the game itself. Change any one of those, and you have a different game.
The question is, "if the story and writing in those games is so absolutely steller why not keep them?" if you were going to make a very different game with some of the trappings of the original. But to my eye, that would be changing one of the intrinsic elements of the game. Taking the same story and putting it in a different game would be the same thing as keeping everything about Fallout 1 the same and putting a new story in it. It wouldn't be the same game to the very same degree that keeping it and making it real-time would be.
Let's say we did both. We'd have two games that both claimed to take the best of Fallout 1. One is a real-time 3D action game with RPG elements that follows the same storyline as Fallout 1. The other is exactly like Fallout 1 in gameplay and design, but a completely different story. Neither would be any closer to Fallout 1, however, because all elements are of equal importance. The story is just as intrinsic to that game as the gameplay.