Elendil's Sword and Sauron's Ring

Originally Posted by Eomer of the Rohirrim

Did Sauron increase his power by making the Ring? It was a ploy to ensnare the other races and it didn't quite work. So Sauron with Ring was no more powerful than he would have been if he had never made the Ring. A powerful Maia. And like Osse says, Melkor - a being far more powerful than Sauron - was given a very decent fight by Fingolfin, an Elf.

So why couldn't Sauron, and his physical body, be subject to a mauling by Gil-Galad and Elendil, a powerful Elf and a powerful Man, even with the Ring of Power? It doesn't seem too far-fetched.

What did the former have in them that the likes of Aragorn and Gandalf did not in the war against Sauron, who could not face him even without the Ring?