It seems here that what lady Galadriel said WOULD happen if she were in possession of the ring, and what would ACTUALLY be allowed to happen by her heart and mind were not the same. What I mean is that , even dear Gandalf, whose sole task on Middle-Earth was to encourage the resistance and only show his power when absolutely needed and obviously directed by Illuvatar, since he said he was sent back , it was not his choice-well even he said that if he had the Ring, regardless of how in the beginning he would want to use it to do good, it would overthrow him and he would end up doing great evil. It is the rings EFFECT upon the mind and heart since it is only evil and not necessarily anything in the person at the beginning. It is like a vile of acid. The first drip or two upon porcelain won't do that much harm, but drip after drip after drip will ultimately totally ruin and destroy the piece of porcelain.So if Gandalf said what would happen should he have it in his possession, why would not the same thing, only according to the Lady's mind and thoughts, do a similar disservice to her and ultimately bring total ruin?
But that does not mean either Gandalf or Galadriel were in any way bad to start off with. And although she did indeed have the desire to rule over her own people in her own place, how is that different from the thoughts and sentiments, NOT the destiny of King Elessar? He didn't enjoy all the pain an suffering and privation that led up to his kingship, but indeed he did desire it and the privelege of ruling over the people in a good and beneficial manner.
Those under Lord Celeborn and Lady Galadriel were not forced to be their subjects, indeed they loved and honored them and wanted to come under their leadership.
So really in my opinion this dark Queen thing is a non issue. :)