Being born with Amber Eyes is a sign of Great Destiny…
Illidan who was born with Amber Eyes unlike Malfurion who gained Amber Eyes during his training as a Druid had the Great Destiny of being not only the first Demon Hunter Mortal or otherwise but also being a Mentor to the Player/Hero of the Story.
Malfurion merely had the honor of being co-leader with Tyrande and the first Mortal Druid yet not the first Druid period. Not only that but he never mentored the Player/Hero unlike Illidan…
Besides Illidan there was only one other Mentor to the Player/Hero and that was Emperor Shaohao and he also was born with Amber Eyes!
Male Night Elves exposed to Druidic Magic gain Amber Eyes very quickly as the Cutscene where Cenarius rejected Illidan as his student shows Malfurion having Amber Eyes despite starting out as a Druid.
This is also not a model limitation as the preceding Cutscene showing Illidan’s birth shows the Male Night Elves with Silver Eyes. Cenarius’s Nature Magic turned Malfurion’s eyes Amber colored while he was still a novice!
This all means that all the male Night Elves from Kalimdor are getting Amber Eyes after birth due to exposure to Nature Magic in some way or another!
Azshara being a Major Villain and first of the Naga is a Great Destiny too which puts her equal to our Mentor(in matters of Destiny and Sacrifice) and first of the Demon Hunters Illidan Stormrage!