This is not tin-foil hat - this is stuff that's been leaked from World of Warcraft Chronicle. Now, I'm typically too much of a snob to buy tie-in novels, but yes, dammit, I've ordered Chronicle because this is exactly the kind of stuff I'm looking for - raw lore that lays out the world we call Warcraft. I've been following a bunch of the spoilers because I'm given to understand that the book's got so much that there will be plenty left to discover, and I just want to get into the discussion asap.
There's always been this question in Warcraft - who came first, the Titans or the Old Gods? The answer to that is kind of... both?
Much as I suspected, though, the Elementals were there kind-of first. To sum up - Azeroth has within it a World-Soul, and the natural order for World Souls is that once they mature, they emerge from the planet... or they metamorphose with the planet into the beings we know as Titans. The Titans never personally visited the surface of Azeroth because they're literally the size of planets themselves - all of their actions were actually done in person by the Titan Forged, including the various Keepers (top rung) and the other TItanforged races, which you'll recognize as everything that underwent the Curse of Flesh to become familiar races we know today like Dwarves, Mogu, Humans, Tol'vir, etc. But I'm getting ahead of myself.
So you could say the Titans, or really "the Titan" was here first because he/she (I'm actually inclined to say she, arbitrarily) literally is what we mean when we say "here." She's Azeroth, a hopefully (if the forces of evil don't get their way) future Titan who is expected to be greater than any Titan who came before her.
But that greatness has a cost.
You may notice that the Elemental Lords on Draenor are way, way chiller than those on Azeroth. Despite Draenor's death-world feel, the lords of Air, Fire, Earth, and Water are actually all cooperative and hang out together at the Throne of Elements. You'd never see Al'Akir, Ragnaros, Therazane and Neptulon doing that.
There's a reason for that.
Shaman often talk about a "Fifth Element," which they refer to sometimes as Spirit. Monks use this fifth element as their source of power and call it Chi. This fifth element is basically the glue that holds the elements together and makes them work in concert. But because of the embryonic Titan within the planet was so powerful, it drew off most of the Spirit element to sustain itself while it grew. The result was that the Elemental Lords and their kin engaged in constant warfare.
At this point I don't know where life that didn't derive from the Old Gods or Titans comes from, but for the most part Azeroth herself could survive the noise on the surface.
But the Elements' constant, fun war was interrupted when the Old Gods came out of the Void, shot as basically massive biological weapons that burrowed into the planet in an attempt to corrupt the nascent Azeroth before she could hatch.
The elementals fought against the Old Gods at first, but were eventually brought under their control (ask a Mage or a Shaman - elementals aren't too hard to control.)
What followed was a period called the Black Empire. Y'Shaarj was the most powerful of the Old Gods and forced the other three, C'thun, Yogg-Saron, and N'zoth, to serve it. When the Titans discovered the corruption, they sent their Titan-forged to battle against the Old Gods. But the Titans are ultimately pretty empathetic, despite our earlier suspicions that they were callous and cold, and Aman'thul decided that he would personally intervene, reaching down and plucking Y'Shaarj from the planet and crushing it (presumably somewhere in those moments gave birth to the Sha.)
Doing so tore a wound in the world - Y'Shaarj's roots went too deep, and Azeroth began to bleed. Mimiron and Arcaedas - two of those top-rung Keepers - built the Forge of Wills and the Engine of Reorigination. Both served to redirect the energy of the wound - aka the Well of Eternity - to keep it from cascading into some catastrophic eruption, and also serve useful functions. The Forge of Wills would guide Azeroth's development and also pump out more Titanforged to settle the world, and the Reorigination Engine could be used to sweep clear the planet's surface in the event that Sargeras' fears were realized and Azeroth became too corrupted.
The three surviving Old Gods were imprisoned. Ra (aka Ra-Den) created the Elemental Planes so that the Spirit-deprived elementals could be separated and prevented from causing further chaos on the surface of the planet. Freya (yes, the one you fought in Ulduar) created the Emerald Dream... or maybe tapped into the Emerald Dream, which might simply be an aspect of the Titan Azeroth's developing mind.
When Sargeras killed the rest of the pantheon, Golganneth cast a powerful spell to preserve what they could of their minds and transfer them into the bodies of the Keepers. This may not have worked all that well, as the only Keeper to truly understand what had happened was Ra. Overwhelmed by the disaster, Ra extracted Aman'thul's essence from himself and stored it in the Vale of Eternal Blossoms. So while the waters of the Well of Eternity are Azeroth's blood, the waters of the Vale of Eternal Blossoms are basically Aman'thul's soul.
Pretty crazy, huh?