[Lush]

I think that the main difference between Galadriel and Aredhel is that the former's strong will is coupled with a sense of logic and wisdom. Aredhel is mostly just stubborn.
I think when she was younger, Galadriel was capable of Aredhel's actions, i.e., I can't see her sitting in one closed-off place (i.e. Gondolin) forever, while not simultaneously being the leader. I don't, however, think that Galadriel would have entered Eol's house without putting up a helluva fight. She could see into people, remember? I think that Aredhel lacked a certain sensitivity, and that this lack ultimately played a big part in her doom. Frankly, I don't think the girl could see farther than her own nose. Then again, you could easily say the same for Turgon. Guess it must run in the family.