Trolls haven't changed in thousands of years? Trolls are the most diverse family of species on the planet, with "original flavor" Zandalar trolls, jungle trolls, sand trolls, forest trolls, frost trolls, dire trolls and dark trolls. They're plenty "evolutionarily adapted".

I've always like the troll/elf theory. It explains the ears.

Evolution is driven by selective pressure. If trolls were already suited to their selective pressure, they wouldnt change much. They might get taller, stronger, bigger tusked, or whatever traits female trolls look for.
If you consider that modern man is pretty much the same as homo sapiens from the stone age, then you'll see that without a major change in selective pressure (or the intervention of a deity), then not changing is normal.
Why the night elves can't accept that they might be related to trolls is most likely due to their own over inflated egos. Maybe their inability to recognise the culture and widespread civilisation that the troll empires created stems from their depressing belief that they are the 'chosen' of a goddess. The way they casually abandoned their brethren when they were in need only increases my dislike of them.

I wouldn't say trolls 'evolved' into Night Elves so much as 'mutated'. That one tribe that migrated to the center of the continent was around the well of Eternity for a long, long time. Is living right next to a powerful source of magic really any different that living next to, say, a large patch of radiation?

I consider Night Elves to be mutant Trolls, much as Dwarves are mutant Earthen (as I don't think being changed by the Old God's Curse of Flesh could be called a 'natural evolution' by any stretch of the imagination).

You know, I hope the troll origin of elves question is never settled. Because, strangely, one of the harder things to do in a fantasy setting is to keep a sense of mystery about the past.

Mostly because fantasy settings tend to have the gods be real and continuously active in the world, lots of immortal or near-immortal beings hanging around, and, in WoW, even time-travel. So the past often isn't something of historical or archaeological research, but rather just asking someone who was there or going there yourself.

And further, when the creators of a fantasy setting create fiction in the setting (whether it be comics, books, or quest text) it tends to be written as "this is what happened" rather than as the best historical/archaeological guess about what might have happened.

For example, we can assume that the War of the Ancients novels are a more-or-less accurate account of the events of that time (until retcon at least, but that's a different problem). And we can assume that the spirit visions in the alliance questline about the origins of the humans from stunted vykul is what really happened.

But the questions about he elven origins are more like the way real history happens. Different groups have different stories, in some ways similar, in some ways contradictory. And there's not enough truly objective evidence to say conclusively.

So, be careful Blizzard. Keep parts of the past an undiscovered country.

Actually it is mentioned that one of the reasons Trolls say the Night Elves evolved from them is to sort of sate their own egos and bruises that they got their butts handed to them by the night elves. They couldnt comprehend a race that beat them cause they were the 'top of the food chain' so the only way they could stomach it was by saying "oh they are just special trolls." Personally I believe the kaldorei were their own race, and became enlightened and more advanced by the well. Trolls are just trolls are just trolls no matter where you find them in Azeroth, no matter what kind of magic etc, whenever you put too much of something into a troll (magic, chemicals, plague, etc) they just turn into beserkers, not nightelves. But as always Metzen has the last word, might be retconned in the future that they evolved from rabbits that drank at the well.

Guys... not all evolution it mean a upgrade. Evolution it is any change in the inherited traits of a population of organisms through successive generations, and that exactly what happen when a small amount of Trolls become Night Elves and when when also a small amount of Night Elves become High Elves.

Technically speaking Elves and Trolls are indigenous to Azaroth i.e. no gods, titans or magical beings created them (only modified them). Thus if you want to talk evolution (which rarely comes up in WoW lore except for 'magical evolution') then yes Elves and Trolls are related just like humans are related to every single other living thing on earth, the question is just where the split off, was it in the primordial pool, was it at a single celled level or multi-celled level, was it when animals started walking on land?

Of course with titans and old gods running around I'm surprised anything indigenous was even able to make it.

Groth:

Who'd actually WANT to be related to a bunch of damned, dirty trolls? Can you mention even one race on azeroth that's any more bloodthirsty, twisted, corrupt, evil and generally perverted than trolls? There's not a single evil entity or demigod on the planet that doesn't have a tribe of trolls worshipping it with cannibalistic blood sacrifices and wicked rituals and whatnot.

Exterminate the lot of them. It's the only way!

The only good troll is a DEAD troll.