Dark Elves are dark purple to black, Nightborne are blue.
Dark Elves do not work with other races, except for short periods of time, Nightborne is allied to Orcs, Trolls etc.
Dark Elves use magic for everything, Nightborne are no more magical that any other warcraft elf.
Dark Elves live underground, Nightborne live in a city.
As I said, there are NO similarities between the two..
Fact (because I say so): TBC > Cata > Legion > ShaLa > MoP > DF > BfA > WoD = WotLK
My pet collection --> http://www.warcraftpets.com/collection/FuxieDK/
Nightborne also have purple skins and Nightborne are AS magical as Blood Elves (probably even more so). They are not to be compared to each other, but to the other races in the game. Their combined mastery of the Arcane leaves every other race in the dust.
Besides, WoW's version of Dark Elves doens't need to be isolationist (although the Nightborne have been for ten thousand years) or live below ground or indeed be a hundred percent match. After all, WoW's version of the High Elves are allied with the Orcs and have a magic addiction.
Suramelves?
Fact (because I say so): TBC > Cata > Legion > ShaLa > MoP > DF > BfA > WoD = WotLK
My pet collection --> http://www.warcraftpets.com/collection/FuxieDK/
Addiction to what now? Oh right, MAGIC.
"The night elves of Suramar don't treat magic callously or lightly, though they used it extensively for everything to the point of being further changed to nightborne. It wasn't the wanton and often gluttonous or abusive use that characterized Azshara's era. Despite the elven love for magic, they did require its use for their survival and thus magic is seen to be employed for everything but also evident is the abundant respect for the source they entirely rely on for life" NEED. MOAR. MANA
Amazing sig, done by mighty Lokann
I think 'drow' is a good shortening. Shame their city didn't get moved underground to make it really fit...
Nightborne literally make their armor out of pure magic. They literally survived on magic for 10 thousand years, and had to develop a process to disseminate the power through arcwine. All of their flora has been manipulated by magic. They have teleportation to get to every part of their city. Their clothing is created by magical means. Magical shields are used in every facet of their design. They have artificial ley built into many of their structures.
Nightborne did pretty much live "underground" in a sense. They were literally cut off from the sun for 10,000 years. They say this many times.
Your other points, yes.
But I don't think dark elves makes sense for them. Not for your reasons--dark elves outside of wow lore have no bearing on the term in wow--but because there's also the weirdness of void elves. Void and dark are too similar in taxonomy--if anyone was going to be "dark" elf, it would be the elves who literally draw all of their power from the darkness and have been physically empowered and evolved from that power.
I think the shal'dorei are too high society to refer to themselves by any other term than Nightborne or shal'dorei. I can see just calling them elves. *shrug* I think the %t replacement text for NPC dialog will be Nightborne.
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What? 10char
Blood Elves were based on a STRONG request from a poll of Asian players where many remarked on the Horde side that they and their girlfriends wanted a non-creepy femme race to play (Source)