The Night Elves suffer from the same writing problems that face the LF Draenei.
The writers wrote them too powerful. I know the RP Guide isn’t canon (even say it isn’t), but they wrote that when Elune enters the battlefield, everyone stops fighting.
Much of Night Elves power, their ultimate trump card, is Elune. In lore she has blinded enemies, killed hundreds of Naga, she’s the closest thing Azeroth has to a God. So, the Night Elves can’t be written properly because of Elune.
If Tyrande prays to Elune and Elune does something besides act as “get out of jail” free card, it’s bad writing because it’s overpowered.
Same with the LF Draenei and their spaceship. No one can compete against a spaceship with lasers. So they don’t write it. It’s why LF Draenei were left out of the Battle of Lordaeron. They could have taken the city in an hour, tops. Archers on the roof? Vaporized. Big walls not letting troops in? Send in the drop pods.
Blizzard wrote this super powerful race, the pinocle of civilization during the time of Queen Azshara, backed by an all powerful Goddess. So they can’t fully utilize them because it’d be bad writing. So they have to handicap them.
How would people have reacted if when Sylvanas rolled up to Teldrasil, and Tyrande prayed to Elune. Then you had wisp raging from the Ashenvale forest, Fulbolg/Wildkin rampaging against the Horde? Every single animal in those forests attacking Sylvana’s army? Beams of light coming from the sky just zapping dead hundreds of Horde units like Elune did to the Naga?
If Blizzard wrote the Night Elves at full strength it wouldn’t be any fun. Because it’s not fair. How is the Horde going to compete against a Goddess? The burning legion tried to do it and Elune barely got involved and the Night Elves still won.
It wouldn’t be good writing for the Night Elves to pull out the “Lol Elune” card. Because then no one would be able to beat them.