As usual, you're biaised.
When she was asked by Terenas to be an Alliance ambassador, and when she freed Alexstrazsa during the second war, she did not acted as "Sylvanas sisters". Sylvanas was a random character at this time.
My comparison is based on your arguments.
He did nothing during several expansions. He did nothing when the Horde and Azeroth were threatened by the Legion & Argus, so he's irrelevant.