I've just come across a point that I've thought about before, and thought it would be good to get some other stances on it. See this letter, emphasis mine:
In the 'Mirror of Galadriel', 1381, it appears that Galadriel conceived of herself as capable of wielding the Ring and supplanting the Dark Lord. If so, so also were the other guardians of the Three, especially Elrond. But this is another matter. It was part of the essential deceit of the Ring to fill minds with imaginations of supreme power. But this the Great had well considered and had rejected, as is seen in Elrond's words at the Council. Galadriel's rejection of the temptation was founded upon previous thought and resolve.
In any case Elrond or Galadriel would have proceeded in the policy now adopted by Sauron: they would have built up an empire with great and absolutely subservient generals and armies and engines of war, until they could challenge Sauron and destroy him by force. Confrontation of Sauron alone, unaided, self to self was not contemplated.
One can imagine the scene in which Gandalf, say, was placed in such a position. It would be a delicate balance. On one side the true allegiance of the Ring to Sauron; on the other superior strength because Sauron was not actually in possession, and perhaps also because he was weakened by long corruption and expenditure of will in dominating inferiors. If Gandalf proved the victor, the result would have been for Sauron the same as the destruction of the Ring; for him it would have been destroyed, taken from him for ever. But the Ring and all its works would have endured. It would have been the master in the end.
Gandalf as Ring-Lord would have been far worse than Sauron. He would have remained 'righteous', but self-righteous. He would have continued to rule and order things for 'good', and the benefit of his subjects according to his wisdom (which was and would have remained great).
-Tolkien, Letter #246
I've always wondered why this was left and not explained. I know in the margin of this letter it does say he'd make good seem detestable, but would he still be helping others? What's so bad about a leader who knows what's best for everyone? Surely that's what a King does after all albeit sometimes very badly.
My thoughts were that he'd be so overzealous with his wisdom that he'd relinquish anyone's free will to the point where people would start taking their own lives for the sake of freedom or there lack of, something I guess which could be worse than Sauron, since he didn't really give you a choice about life or death.
So what's everyone else's thought on this? BTW, I looked around the web for an answer or at least something on this, and very little popped up for me, so I thought it would be a good question.