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).

I fail to see how this description is 'far worse' than Sauron. It seems to me far better than Sauron, who certainly wasn't ruling according to any conception of the good of his subjects.