It depends on the bread. If a bread has real character, toasting is, as lady penelope said, an abomination. If it's run of the mill bread, though, a light toasting does a bit to alleviate its blandness.

It also depends on the degree of toasting. Toasting to the point of crunchiness may be fine for breakfast toast, but not for sandwiches. Any real crunchiness that comes from a sandwich is supposed to come from its ingredients, not the bread.

What I really cannot abide is steamed hot dog buns. Yuck! Why take something that already has no texture, flavor, or character and put it in a steamer so it becomes soggy and doughy as well? Toast that sucker until lightly browned!