Such as, say, a well of energy that draw upon the power of the sun? A Sunwell of some sort?
But facetiousness aside, the Naaru or someone else deeply steeped in the light are likely capable of catalyzing another Sunwell into existence and even then they require an immense source of arcane power to act as the reactant. For the reignited Sunwell it took 1.) The corpse of a Naaru, 2.) The old power of the Sunwell in human form, and 3.) Prophet Velen performing the deed.
So we're probably still going to have to punch Illidan in the face or retake Karabor to get the power necessary to have the base components to begin creating a new power source for the Blood Elves.
And, to articulate what I had thought was going on with the Manaforges. I'd thought it similar to trying to get at that delicious delicious radiation in space but that pesky Ozone and atmosphere is in the way, so they punched through that protective bubble and made yet another oozing wound in Draenor.