Except she can't DD. Why do you think she had to have Skieth do it to Sora?
Ok, just to tell you, Morganna could've gone after Tsukasa the whole time. Even if she was omnipresent, she would still have the power to transport to another field.
Omnipresent = everywhere at the same time.
IE, she couldn't teleport anywhere, because she is already everywhere. See? And if she could have gone after them, why didn't she? Why is she messing around with the Phases and Skeith? Why not suck Kite into her dimension and destroy him?
'cause her power is limited. She can talk all she likes, but her power to affect things isn't there. Hence the Phases.
(Note: She was able to hurt Tsukasa during .hack//SIGN, but only in her little Bubble-Area. She never affected a player outside of it.)
"A friend... or perhaps, a foe. A meddler with a warning." -Helba, .hack//Infection