Remember she covered the ENTIRETY of Darkshore in an eclipse to empower the Night Elves and the Worgen. That is a zone wide intervention which allowed the Alliance, specifically her worshippers, to push the Horde back during the war. In the ancient wars, Elune had pacified an entire battlefield temporarily to allow her worshippers time.
Of course nobody is saying Elune has the power to intervene in all events. She may have limitations or CHOOSES not to intervene. Like she CHOSE not to intervene when the tree was burning because she wanted those souls to fuel Ardenweald. Here are some of her feats:
• Elune has the power to strengthen her worshippers and has done so in the past with empowering her priestesses.
• Elune bestowed Shadowmeld to the Night Elves.
• Elune created the wildkins.
• Elune created the nightsabers to be black/silver.
• Elune has ties to the Titans because one of the Pillars of Creation is her tear (The Tear of Elune).
• Elune is older than the Titans as she has connections to the Eternal Ones who predate the Titans.
• She spontaneously created a shield around Tyrande that kept her safe from Archimonde.
• Khadgar stated Elune created the first prime Naaru.
• Elune easily cleansed Sargeras’ corruption from a satyr. Elune also converted him back into a Night Elf.
• Elune easily cleansed Ysera’s corruption and sent Ysera’s spirit to Ardenweald.
• Elune gave IMMORTALITY to Omen.
• Elune made Tyrande immortal temporarily when she was being held in Azshara’s palace. The Highborne could not torture Tyrande because of Elune’s blessing. When they tried to starve Tyrande to death, Elune made it so Tyrande didn’t need food to survive. How is this a simple feat lmao
• Elune has shown visions of the past and future to her worshippers.
• Elune pacified Saurfang and made it so he couldn’t bring his axe down to deliver the finishing blow on Malfurion, thus saving Malfurion using divine intervention. She also guided Tyrande to where Malfurion was so she could rescue him.
• Elune shrouded all of Darkshore in darkness for an extended period of time.
• Elune stated to the Winter Queen that she sent a flood of souls to Ardenweald meaning Elune has the power to direct A LARGE NUMBER OF SOULS from place A to place B. Her divine intervention isn’t limited to helping one person at a time rofl
• Elune is one of the only entity in Warcraft that is portrayed to be truly godlike. We don’t know if she even has a physical form. Her powers are all over the place and her interventions are known to be “divine”. She is worshipped like a God not only on Azeroth but across the Twisting Nether.
Elune is complicit in the burning of Teldrassil and it is evident from the recent cinematic. Delaryn and Sira were of course right when they said Elune had abandoned them. Elune did not stop Sylvanas because their goals aligned. It’s that simple.