[A_Brandybuck]

Sorry, I would say, that Tolkien included exactly the right details concerning Gil-galad in FotR. I think, that the attraction of 'Lord of the Rings' comes inter alia from those things, which Tolkien only indicates.

I still know, when I read 'Lord of the Rings' years ago the first time, I was very fascinated from the background of the story and it quickened my appetite for more stuff concerning Middle-Earth. The details of Gil-galad, the former life of Elrond and the existence of a mysterious island called Númenor were those details, which leads me to the Silmarillion and the Unfinished Tales.

A deeper background of all these things included in 'Lord of the Rings' would make the world less interesting in my view.