Leaves In hair, good ponytails. Maybe a better set of braids.
Different types of eyes, some of the art work have Nightelves with visible retina. More facial tattoos, more faces.
While they are at it, please fix the sharp edges on the hips…
And I need my heritage armor… along with all of the other races that don’t have it yet.
Highborne options, definitely Highborne options.
Surprised no one has mentioned Night Elf Mohawk! 
We already have a mohawk
Forgot to elaborate, Night Elf Mohawk for girls.
Or even this hairstyle:
i’d like some body shape choices for all races
Yes. The Keepers of the Grove already have leaves on their hair. It wouldn’t be difficult to add them since it’ll be the same as the Void Elves’ tentacles
Feather earrings
Highborne earrings (hanging unlike the Nightborne’s “ear armor”)
New markings for Death Knights
Hair Styles & Facial Hair
Skin Tones
Markings
Eye Colors
Accessories
Leaves in hair, earrings, different eye colours (gold, silver, purple, green and night warrior black), a lot more skin tones, new faces, more hair colours and styles including black hair for all classes not just demon hunters.
The druidic shining tattoos that some night elves have and some shining facial tattoos similar to females.
Obviously, eye color swaps.
Tattoos… maybe some non-grumpy faces for males…maybe some non-happy faces for females… eyebrows for males.
More short hair options for males.
Black hair.
Not really. They can give us new tattoos, too. Ours don’t glow. We can also use some different eye colors. Females should be able to have golden eyes and males silver. The leaves in the hair would be cool. And males being able to have eyebrows without facial hair would also be nice.
Nightborne don’t have anything to do with that stuff.
Antlers like our friend Malfurion!
Not really… besides a lot of NB customization was scrapped anyway.
faces that aren’t completely disgusting.
So… Everyone and their mom will have tattoos it sounds like. Sounds amazing and not at all like they will make tattoos boring. Oh and two eye colors instead of one.
Anything else you can think of? How about… NB customization for NEs since they are the same thing? The same as a forest troll vs darkspear or a mechagnome and a gnome anyway.
I’m hoping for some hardcore Highborne customisation. Tattoos and leaves in hair sounds so mundane.
Personally I’d like them to have more glowing stellar tattoos, and have them able to be decorated around the body. Y’know – Elune-y kind of vibes. 
It should be the reverse. More longer hairstyles for both sexes