There are differences now between the Rand who would not/could not use the full extent of his power on Lanfear at the docks and the Rand who came down changed after his epiphany on Dragonmount.

The "old" Rand had the same scruples as the "new" Rand. He still has an extreme distaste for killing or allowing the killing of women. The big difference is that he has now grown up. He is not unlike a lot of people in this world today who have pie-in-the-sky dreams of what a world would be like if only people were nicer to each other. As an ordinary joe--no big deal, just out living my own life--anyone can indulge himself in the high-minded ideals of Rand's (and Perrin's and Mat's) upbringing. When you assume a position of power or influence, though, pragmatism takes a much larger role than idealism. There are bad people in the world, and they have to be dealt with in ways that some people have a hard time stomaching. The Rand of ToM would have destroyed Lanfear on the docks--not because he is more cruel (that Rand would be the Rand post-attacking-Min but pre-"moment-of-enlightenment"), but because he knows that he has a duty to fulfill that takes precedence over his distaste for killing women. He cannot allow her to destroy him, the mountain that he carries on his shoulders cannot be eased in that way.

The younger Rand would have thought his "rule" about killing women to be inviolate; the wiser Rand knows that nothing--not even the destruction of a woman here or there--can be permitted to interfere with the completion of the responsibility that is his, uniquely and completely his.

The younger Rand would have thought that he could find some way out, some other option that would allow him to live and still not break his precious rule. The wiser Rand would have known that it was his responsibility to act in a distasteful way then (slaying a woman) in order to avoid an even more distasteful event (sa-a-a-a-y... the total victory of the Dark One) later.

It's not like it's just Rand who does this. I find Gawyn's inability to listen to Egwene's words about knowing what she is doing more troubling. RJ and BS both seem to crack down on him about that particular peccadillo--right up until the point where it actually saves Egwene's life.

I actually find myself on Perrin's side when he goes through the same thing with Faile. "I'm sorry, dear. Yes, I love you. It's just that I was raised to not raise my voice--let alone my fist--to a woman. Any woman. Especially my own wife." I get the idea of Faile's frustration. She doesn't want Perrin to think of her as some fragile flower that needs protection. Bu-u-u-u-ut... At the same time, she wants him to "grab her by the scruff of the neck and show her who is stronger" (to quote her mother).

There is definitely some contradiction in the expectations here. Not unrealistic ones. In fact, those contradictions--and the confusion and frustration they bring to characters of both genders--are part of what makes the series' interaction between genders so... well... so real.