This is my first exploit posted on this site, hope you guys like it. I'm going to get straight to the point, Omen does NOT reset his health after wipes/players running away.
Players can solo him but he has 5.5mil health so it would take a long time (Hydross, anyone?)
Simply do dps from range while running away, cause him to de-aggro and repeat.
A more practical use for this is when your raid only has 1 healer, attempt the boss anyway until you run out of mana, run away from the boss, drink up, repeat.
Edit: Removed the evil word 'theory', although I know for certain people can solo him. Seriously, when you see the word theory and know its true, use common sense.