[Eldy]

Originally Posted by Hookbill the Goomba

this probably has a lot to do with the fact that Sauron probably can't 'die', being a Miar.

I agree that it has a lot to do with Sauron's nature as a Maia. However, while he does not die in the normal sense, he is permanently disembodied, which is much like what happens to Elves and Men when they die. In a way, becoming an impotent spirit in the wilderness seems a fate worse than death to me.

This is another way in which The Lord of the Rings differs itself from many others.
I can't help referencing The Lion the Witch and the Wardrobe wherein the White Witch is ultimately killed by Aslan. Or His Dark Materials where god is killed or Harry Potter where Voldemort meets that same fate.

I've never read His Dark Materials, but in the other cases, the antagonist is not killed by the hero, per se. Certainly he dies, but it is somewhat indirect. In TLtWatW, it was as you point out Aslan, not one of Pevensies, who killed the White Witch. In Harry Potter, Harry's innocence was preserved since he cast only a defensive spell and then other forces kicked in. It's not the same as TLotR, but the hero still doesn't actually kill the villain.

Whenever there is death in the story, they at least see the victim, it seems.

No one sees Sauron.

That is a very good point, and not one that I had thought of before. We certainly see the deaths of other villains, notably Saruman and Wormtongue, directly.