[tifo_gcs]

I argue that Greatness is a quality all in its own right. Saucepan, you say that "A great evil arose..." In this case, you use great as an adjective describing evil. I contend that it is possible to use Greatness as a noun, just as power is a noun. In which case, I choose to define greatness as a positive thing.
Given therefore that greatness is a positive thing, I will now further contend that those who posess greatness in Middle Earth have greater power than those who are great evil (Note greatness as noun, great as adjective). I base this on the observation that Gandalf, being on eaual rank with Sauron in the hierarchy of ME (both Maia), defeats Sauron's alliance of evil with his own alliance of good.

Gandalf has greatness as a quality due to, as saucepan man says "his wisdom, his judgement and his strength of mind," not to mention his kindness, care and concern for all living things. Now I realize that that quote comes from a description of Gandalf's power, but I think we can all agree that Gandal has those qualities. To contrast Saruon has hatred, fear, greed, sentiments which I think we all can agree make negative character traits

There is also the example of Boromir vs. Faramir. Boromir has great power, the trust of his father, he is a renowned captain, with courage and skill. However, he lacks the mental capacity that Faramir has, for being just and kind and, above all, wise Faramir, who is also skilled in the arts of war, and also has a good reputation, but who also has the proper mindset of being able to reject the ring, while also being kind and fair.
End result, he lives, Boromir dies.

Greatness is in my opinion a mental factor that has to do with wisdom and goodness, and I believe that greatness increases the power of those who have it.