The Greatest of the Eldar

[Maédhros]

Tolkien does not put conditions or limitations on Luthien's greatness. The issue of her greatness isn't bound up in her deeds or her specific "powers," either. It was just damn good genetics.

I can agree with the fact that Luthien was the greatest overall elf.
What I was trying to know was what was the author intention when he wrote the quote provived by obloquy.
Is she the greatest artisan or warrior, etc. I don´t think so. I think that the author meant that she had the greatest overall spirit or qualities. She was the best overall, not in certain specifics areas.