Originally Posted by
Engal
Doubtful, or Blizzard wouldn't have thrown this if it wasn't important. It was one of many hints at Elune true nature. Most of the time, when it's stated in a quest text like this, it is true. Moreover, the inch Kadghar had worked. The Power of Elune opened Light's heart.
I think you misunderstand the power scale here.
The first one basically ordered the universe, they shaped it. They -apparently- created and shaped all the forces we know. They shaped Life, they shaped Death, they shaped Order, they shaped Void and Light, ( fel is another matter since it seems to be the garbage part of the universe )
The titans cant shape and change how the plane of life, the plane of Death, the plane of Light, The plane of Fel works, etc. They can only use what is at their disposal and was already there.
The titans can shape and change the shape of continents and planet, or alter the timeline etc, but can't change the rule that are behind those. They can't create a new world soul from scratch, for example. Your logic implies that a Titan could completely rewrite the plane of Order and remake how things were set by the First Ones. They have to follow the rules they set because things have been written to work a specific way.
They can't diverge from those rules.
Do you understand why Zovaal wants to reach an higher goal ? He can rule over the plane of Death but can't change the way it works or it's been constructed, unless he reach something in the Sepulcher, that will help him rewrite the cosmos and how the rules were set ( apparently ). That's the whole reason behind Sylvanas' speech.
On the contrary, Elune can turn a soul into a full constellation, that is a First One-like Power. She can create beings of Light, she can influence Life and do things in the Emerald dream. She can use Arcane power and landed her power and protection to Eonar. She can infuse a Night warrior with void-aligned power.
If she's not a first one, she's close to one. And I'm pretty sure Zovaal's goal is to do something that will ascend him to what is Elune or above, because she already did in the past.
I'll go further by theorizing that Zovaal discovered that the power of the First One was a borrowed power they stole from something , and is a power that can be acquired, and that the First One are a fraud leeching on the power of something else, that is in the Sepulcher.