Pandaria is south of the equator on all parts of the map. And yes, it’s kind of smaller on the map than shown in-game, about half of Northrend’s size. I do think it should be bigger.
And yes, I think the continents are small. The post-Sundering ones, anyway. Ancient Kalimdor was large in comparison. If Azeroth is about the size of Earth, ancient Kalimdor was about half the size of all of Earth’s continents taken together — or at least that’s my impression.
More than a few NElves have lived over a thousand of years and you just need to look up a timeline to see they have been in several wars through that time. True, you could argue it’s not been constant war, but then you still got the experience from surviving those wars and gained from training afterwards and if we factor in they are (well were, until Blizz kinda forgot) a very martial culture, they likely put importance on everything from personal combat skills to strategic and tactical understanding you should have had a race with such a deep understanding of warfare that it’s actually pretty scary. I would gladly concede my point if warfare had changed drastically, during their time, but it really has not. On a surface level it may seem to have but it really only have to a very little degree, so only minor adaptation, if much at all would be needed.
“Elegy” states that even night elven civilians are capable of some fighting. So you can imagine that soldiers have kept up training etc.
And there have probably been smaller conflicts, as well, even if they weren’t full scale wars.
Immortality is one of those concepts that is very hard for us humans to truly wrap our head around. It is as you say an incredible power. The amount of things you could learn in 10 thousand years is insane. The last ice age ended ~11 000 years ago, Tyrande and Malfurion are probably around this age or a bit older. That is an almost unfathomable amount of time for us.
It apparantly takes a human (in reality) around 10 000-25 000 hours (depending of course on the quality of the practice) to become an expert at something. Unless the night elves had a severely hampered ability to learn, imagine how many skills they could master in that time!
But i think we can rule that out slow learning since we have encountered many “younger” night elves and they are obviously not comparatively stupid to us. Also, if they were extraordinarily slow learners they wouldn’t have conquered like 90% of the known world and then and quickly decided that magic=bad after the WotA.
Time is something very strange in fantasy worlds though. I mean look at Westeros: The long night, the last invasion of the army of the dead and the white walkers apparantly happened ~8000 years before ASOIAF/Game of Thrones. Their technology have basically been stagnant for 8000 years. 
Elder Scrolls online takes place 800 years before Morrowind. Skyrim takes place 200 years after Oblivion. Elder Scrolls racial societies/technology hasn’t development in over a thousand years.
This is one thing that always bothers me about fantasy settings, and WoW is just one of the worst for it. I’ll never understand why fantasy writers can’t just go with a few hundred years at most.
I’m sure some diehard Elder Scrolls fanboys would be able to explain why this is to you in a very confusing fashion, complete with thirty-two mentions of the term ‘CHIM.’
But warfare has changed. The Horde has mana bombs, azerite tanks, iron stars, death knights, war mages and all kinds of other developments that didn’t exist during the Long Vigil.
This is why Lintian believes that her people’s refusal to change and adapt to the times was a major factor in their defeat in the War of Thorns.
Actual good point right there, though they did allegedly use guns by the time of cata. We saw no such thing in the sad end of kaldorei civilization.
Hence my point was “drastically” which it has not since The Third War, which the NElves also participated in. It’s still largely a frontline of grunts/foot soldiers a second line of riflemen/archers and then various forms of support such as steamtanks and catapults, we see hints of this both in cinematics and in the game itself. Gyrocopters and the use of flying mounts are not new either.
Pretty sure during the battle of Mount Hyjal the NElves also fought a Death Knight or two.
So we add all the previous experience they are supposed to have had, their newly gained during the The Third War, like 15 years or so ago, that’s more than enough time to get an understanding of “modern” conflict to form a more than a solid base upon.
The War of Thorns just adds to this ridiculousness, basically even if you want to ignore everything else I said, the NElves are masters at guerilla warfare and somehow, a giant army snuck up on them on their home turf, in a dense forest where they literally communicate with the forest spirits. This is not just being unable to change to the times, this is incompetence on a colossal scale.
More accurately put Westeros has been stagnant for six thousand years; the First Men during the Long Night were virtually no different from the Freefolk except for in one regard - the Freefolk actually has access to weapons of iron and steel. The First Men wielded weapons of bronze until the Andals invaded and brought with them the Faith of the Seven, knightly ideals and chivalry, and most importantly for Westerosi society overall, I’d say - weapons and armour of steel.
But technically that isn’t right either, since Westerosi society and culture was radically torn down and re-built by Aegon the Conqueror during his War of Conquest 300 years before the War of Five kings. We have seen new an innovative designs, though, like Joffrey’s crossbow.
But that is where the universe of ASOIAF differs greatly from Warhammer, WoW, LotR and virtually all other universes; Westeros’ stagnant, backwards state is something that is widely acknowledged in-universe, especially by the far more ‘civilised’ and technologically advanced and capable Essos and its many radically different nations - sans the obvious likes such as the Dothraki.
All of Tamerial is in a constant dark age with every Era bringing forth Oblivion of some kind or another.
Additionaly I imagine the Daedric Lords and the Gods got a hand messing with anyone trying to uplift technology, like the Dwemer.
There is also the weird meta-lore that Elder Scrolls has, with that everything, litterally every life, every time, every single thing that exist or existed, is all a dream inside some sleeping cosmic thing. Hence explaining away things that are illogical, because its all shaped by the dream.
It’s also in that part of the lore, that characters who become self-aware that they are part of the dream ceases to exist, unless they are “strong” enough, then they can shape things as they wish and become god-like, example of this being Talos.
Example of someone -not- being strong enough and thus being erased is that weird priest guy in Skyrim who is working for Hemaeus Mora, and evaporates once he gains hold of the Infinitum book since it gave him the knowledge of everything.
Sounds more like a theory, though there were that incident with the Warp in the West, eluding to all the endings of Daggerfall being equally true, but thats the beauty with Elder Scrolls lore to begin in my eyes, we know so very little about everything outside the realm of the mortals,
Like the Scrolls the entire franchise gets its name from.
It is as far as I have read up and think, official lore, with alot of speculations around it. Look up “The Godhead” for more reading on it 
.
But yeah, I do very much enjoy Elder scrolls for not doing the thing Blizzard does, in that litterally every piece of info, especially what we -don’t- want, needs to be elaboratly explained and demystified, both in character and out of character, leaving very little up for speculation and theories and interperations.
They really love doing the “this is the 100% fact everyone knows is also 100% fact undeniably”, which removes alot of the wonder of fantasy.
Indeed, and then they change this 100% lore correct fact next expansion.
While the ending of Trinimac and origins of Malacath remain vague and yet pretty straight forward at the same.
That Gnomeregan was reclaimed long ago and the Gnomes now live long and prosper!
I may be an Orc on the surface, but in here, I’m a Gnome with neon green hair.
That there are many elves across both factions who would like to band together as a third faction instead of allowing themselves to be bound by either the Alliance or the Horde.
*raises hand*
Reclaiming of Gilneas would be a head canon for me, i guess. We are trying to do something there, but we would really love for Blizz to come aboard that train and actually make it a reality.