Originally Posted by
Razion
I could imagine if Thrall got to the Night Elves before the Tauren or Trolls Thrall would have probably leaned to respect the forests in the name of preserving balance with the elements. But if that happened Thrall may not have saved Cairne, so the Tauren would have been wiped out by the Centaur. And if Thrall also didn't rescue the Trolls by the Naga, they also would have been wiped out. Since Orcs would be protecting the forests, and Goblin shredders with the Venture Co. would be running rampant for resources in their zones, it could be that the Orcs would never recruit Gazlowe to help construct Orgrimmar, which basically puts the Orcs in Darkshore closer to the Night Elves to be mutually beneficial.
I could probably imagine the Orcs close to the coast-line in order to fish so they disrupt as little forest as possible while they continue to adapt to druid culture. And if the Orcs were occupied in Darkshore, then the Night Elves may have turned to the Orcs to actually fight the Shatterspear that threaten the Night Elves in a small part of the zone which would have potentially tainted any future relationship the Orcs would have with Trolls going forward.
As well, if the Orcs were busy helping the Night Elves on the other side of Kalimdor, this means Thrall and Jaina wouldn't have had as much of a friendship and the early tentative peace between Orcs and Humans would be even weaker than it was back then - possibly even jeopardizing the unity of Azeroth's forces against the Burning Legion's invasion during the Third War and the Battle at Mount Hyjal. However, it's possible that with the Orc's aid that the World Tree Nordrassil would never be lost and the Night Elves could have kept their immortality.
Going forward, this means that Teldrassil would probably never have to be planted, and it would never be corrupted - leaving the Emerald Dream devoid of taint and allowing Malfurion to take on a much more active role in Night Elf society. And as Malfurion isn't lost to the Dream and his sleep influenced by Fandral Staghelm, it's possible that Fandral would have been ousted earlier and his eventual fall to Ragnaros would have been avoided as well. Since Thrall was so instrumental in stopping the demonic influence of Ragefire Chasm, he may even play a role in dismantling demonic threats to Night Elf culture in general.
When C'thun unleashes his invasion with the Qiraji, it's possible that the Orc and Night Elf combined forces would be overwhelming to the Old Gods, forcing them to re-prioritize their efforts to try and hinder or otherwise corrupt Night Elves and Orcs. With the Orcs and Night Elves basically keeping to themselves in Kalimdor and with the Orcs on a far less friendly set of affairs to the Humans, it's less likely that the Night Elves or Orcs would have lent aid as early to stop the Scourge forces of Naxxramas before it became a much bigger problem and ended up threatening more of the world. The Lich King by extension would probably sour any remaining inkling of hope for peace between the combined Night Elf and Orc forces to the Humans. And, assuming Humanity isn't wiped out by the Scourge it's possible that the Night Elves and Orcs may even finish them off to prevent something like the Lich King from happening again. Yet, without Humanity the Night Elves and Orcs wouldn't have the might of Tirion Fordring for the eventual needed crusade to dismantle the Lich King. However, with the immortality of the Night Elves intact it's possible that they would overwhelm the Lich King's undead forces.
With the Scourge having more reign over the Eastern Kingdoms earlier, it's possible that Quel'thalas and Undercity could have fallen to the Scourge before the Night Elves and Orcs got around to helping. Though, it's also possible that maybe Illidan's conflict with Arthas may spur the Night Elves and Orcs into early action against the Lich King as well.
With Orc and Night Elf culture mingling for so long before Cataclysm, it could be that Thrall could have ended up taking on Druidism rather than Shamanism. Without his work at the Maelstrom, Thrall would never have left Garrosh in charge of the Horde which would eventually no doubt lead to a lot less bloodshed but it would also mean that Thrall wouldn't be tending to the Maelstrom and he may also not be able to act as surrogate Earth Aspect in order to stop Deathwing. In an ideal timeline, Thrall would probably remain as a Shaman and somehow Tyrande or Malfurion would be able to lead the Orcs in his stead while the other of them manages the Night Elves during the Cataclysm. As long as Thrall is able to eventually act as Earth Warder for the Dragon Soul, Deathwing can still fall. Though, it's possible as well that the Night Elves with their immortality could be a significant threat to Deathwing by themselves. However, due to the conflict the Qiraji could have had against Night Elf and Orcish combined forces earlier augmented by the Night Elves' immortality, it could mean Deathwing breaks through and goes directly for the World Tree first in order to take its protection away -- again leading to a timeline where Thrall still needs to act as Earth Warder.
If the Blood Elves fell earlier to the Scourge, this would mean that Kael'thas wouldn't have had the opportunity to summon Kil'jaeden to Azeroth. As well, with the Orcs' history with the Draenei, it's possible that even though the Draenei were assisted by the Night Elves that they never would have united. Ultimately the Draenei would be necessary to dismantle the Legion and eventually the Void according to the prophecies of Velen, so it's also possible that Velen would have still pushed for his people to ally with the Night Elves and Orcs when it is necessary. The Worgen may still have their wall broken down - either by Scourge, or by Deathwing's upheaval. It's possible the Worgen still end up in an alliance with the Night Elves due to their connection with Goldrinn, but it's also possible that their humanity at this point prevents any kind of alliance with the Night Elves and Orcs. It could be if the Night Elves ever understand the strength the Worgen have over the Undead, and if their strength would be needed at all, that maybe a tentative alliance is formed that allows them to work together long enough to assist with removing the Lich King from power.
If the Human kingdoms fall too early to the Scourge, or even if the Eastern Kingdoms fall to the Scourge early, it could mean that the Dwarfs don't end up making it to Northrend. Without Brann's archaeological findings of Ulduar, it's possible Yogg'Saron would have a tight grip on Northrend in the event the Lich King was dismantled. However, with Malfurion and Thrall instrumental in this potential offensive on the Lich King, the taint of the land may still be discovered and yet may still be stopped regardless.
With Garrosh never coming into power, expeditions to Pandaria never happen and Pandaria faces a significantly weaker Sha threat (just Mantid) - but they also don't get assistance against the combined Thunder King and Zandalari forces. With the Darkspear earlier wiped out to Naga without the aid of Thrall, and with the Thunder King and Zandalari victorious in Pandaria, Vol'jin would never ascend to Warchief. And again, without Garrosh coming to power, the Iron Horde is never created and never makes its way into the main world of Azeroth. And now, in current events, if the Forsaken are dismantled by the Scourge early, this means that Sylvannas' genocide of the Night Elves doesn't occur and Sylvannas' breaking the ceiling of the world into the Shadowlands wouldn't happen either.
In this kind of reality, the ending race combined forces may look something like this for the Core Races:
Elven Horde: Night Elves, Orcs
Isolated/Uninvolved: Dwarfs, Gnomes
Hostile to Elven Horde: Goblin
Potential Allies or Neutral: Draenei, Worgen
Potentially Extinct: Tauren, Trolls, Forsaken, Blood Elves, Humans, Pandaren
As for Allied Races, the Zandalari's primary empire would possibly fall to G'huun without the aid of Azeroth forces, unless the Thunder King and the Mogu took action to stop it which is well within their motivations to do so. It's possible Zandalar would still fall, and that Pandaria would still be a dominant seat of power for the Thunder King and Zandalari, with the Zandalari greatly weakened by G'huun initially being unleashed. Without any reason for the Night Elves and Orcs to be in Pandaria or Zandalar, the Night Elves and Orcs may never be called to action to help stop the Old God until it reaches its influence beyond Zandalar. And with the fall of Zandalar, Vulpera would perish. If left unchecked, Kul Tiras could also fall. Additionally, with the Gnomes not present for the battle in Ulduar, Mechagnomes don't become a thing. Dark Iron would never end up allying with the Dwarfs without Wrynn around to unite the clans unless they all unite against the Scourge, or if they ever held out long enough for Moira's son to get the throne. Void Elves may not exist if the Blood Elves got wiped out by the Scourge earlier.
As for Dark Iron, them working to unleash Ragnaros may go uncontested for a while, as Orc forces wouldn't be as invested to go into Blackrock. Ragnaros would probably pose a very real threat to the World Tree if it hadn't already fallen to Deathwing. The Old Gods, if any remained hidden long enough or bode their forces well enough, would probably put a lot of their effort into trying to back Ragnaros. The Dark Iron would ultimately end up hostile to Night Elves and Orcs as they would almost entirely be siding with Ragnaros. Though, it could be that the Dwarfs and Gnomes having an entire focus on them could dismantle them early, assuming they weren't obliterated if the Scourge was left unchecked long enough to dominate the Eastern Kingdoms... so maybe Ragnaros doesn't even happen anyway.
Nightborne and Highmountain would remain in similar isolation in all likelihood, but would still remain as potential allies for the Night Elves and Orcs. Lightforged would at the very least would ally with the Draenei, and considering how willing the Lightforged are to work with Orcs in ending the Legion would probably be more receptive than not of past transgressions - especially considering the turn of face the Night Elves have probably done for them in all good influence.
There's absolutely a ton of what-ifs for all the races, but for Allied Races this is how I think it could look like:
Don't Occur: Mag'har, Void Elves, Mechagnomes
Probably Allies to Elven Horde: Nightborne, Highmountain, Lightforged
Potentially Extinct: Zandalari, Kul Tiran, Dark Iron
If Living, Hostile: Dark Iron
It was a lot to get through but I like to think I covered a lot of ground.