Your lack of faith in the prowess of Dwarves troubles and disappoints me, Matt.
I remember a discussion years ago about how the story would have felt had Frodo and/or Sam laid down and died after the destruction of the Ring. That too might have been realistic; but as Saucepan Man argued (I remember it
) such an outcome would have been unnecessarily grim in a story that is meant to delight the reader. Same goes for the Elf and the Dwarf - no need to harm them, we like them.
Besides, though it would have been beasting to see Legolas fight on with one arm severed and hanging off the shoulder, he displays possibly equal awesomeness in avoiding injury completely.