I don't think there is any credible argument that any single film is the do-all for this kind of work. I have many different films in the bag when I go out; I assume everybody does.
It so happens that I do shoot a lot of velvia 100. I had a situation when it did something very nice for me: I was in monument valley and there was an unusual late spring storm that had the whole valley under very heavy cloud. The range in the scene was very small: the light would have been dead flat to anything but velvia 50 or 100.
But I have also had situations when I felt that either astia or provia 400x was more suited to the task than velvia, or when it was clear that a good print film made a lot more sense because of the range in the scene. If I had to pick one film for the grand canyon then... well, forget it, that's just not a realistic constraint. Take a velvia and one of the new ISO 160 print films and be happy.
I didn't have a good time with 100F, but it's not even worth telling you what my impression was, it's something one has to try for onesself.
Regarding "exaggerated saturation" in velvia: well, when I look at a colour scene, if I think strong colouration is inherent in a scene and plays an important role then I reach for a film that will deliver that message. Obviously I don't take pictures of grey walls with velvia. People sometimes intone that velvia is somehow lying about what's there. Look, every photographic film imposes a particular personality on a scene. We like that and that's why we have different films and not just one digital sensor with "optimal colour fidelity," whatever that means. We just have to learn how to use the personalities of the films as a tool rather than a gimmick.