What if... the Great Link, long before the dominion, evolved on Vagra II, and then learned to improve themselves by leaving the negative hateful pitiable elements behind, boiling them up to the top and letting them dry out like tomato soup skin, and then the rest of them left the planet en masse?
[FONT=Arial, Helvetica, sans-serif][SIZE=2]ARMUS [OC]: I am alone.
TROI: Abandoned. Who deserted you?
ARMUS [OC]: Creatures whose beauty now dazzles all who see them. They would not exist without me.
TROI: You were together?
ARMUS [OC]: They perfected a means of bringing to the surface all that was evil and negative within. Erupting, spreading, connecting. In time it formed second skin, dank and vile. [/SIZE][/FONT]
The Great Link would then be spaceborne (which we already know they can do, migrate en masse), and leave the black oil behind to stew and eventually become Armus, who can't create a solid form complex enough to escape the planet's gravity or atmosphere (UNLIKE a normal changeling), but who *can* effect a certain degree of psionic capabilities, such as the telekinesis he uses to mess with the Away Team, and how he messed up the Shuttle's energy in the first place to force them to crash when they got too close in passing Vagra II. Whatever makes him pure evil also gives him those abilities, so it's something that the Changelings left in the Great Link can no longer do.
THEN, much later in the future, the Great Link ends up in the Gamma Quadrant... And they try to integrate peacefully with solids at first, who mistreat them and hunt/kill them...
THAT makes them insular, it makes them sit and seethe... they see themselves as more evolved than the solids, more "good," less "evil" and given that solids kill them, they feel suitably justified in their arrogance. So they decide, partly out of arrogance and partly out of self defence, to organize... to build a defence, to build an empire, as much to "guide" the solids as for their own good. And thus, the Domionion is born.
They don't necessarily see themselves as evil, do they. They just look with intense disdain on solids, and they feel themselves superior - godlike. To them, their inherent superiority justifies their galactic mischief.
What say you?