His inability to kill women is a result of him killing his wife in the AoL combined with a good upbringing in his new life. The more he remembers of his life as LTT, the more he can't hurt a woman. Then his insanity takes over and he starts to hold onto this shread against all rational thought. The scene with Lanfear at the docks was a little over the top given Rand's development as a character at the time, but you also have to remember that he only THOUGHT he could easily kill her at the time. In reality, he was barely able to hold onto saidin, and his attempts to call lightning or fire down on her probably would have failed considering how unskilled he was at channeling at the time, how skilled and powerful Lanfear was, and his position during the battle of basically being defeated and hardly able to hold onto the power.

He was going to balefire her. He was barely trained and not remotely close to his full OP strength and using an average angreal, while Lanfear had an almost sa'angreal (Moraine planted).

The current Rand would likely defeat a full strength Lanfear with the same almost sa'angreal. Men are much stronger in the Power, and LTT is the most powerful and skilled.

Did Brandon make an error in the scaling of the Choden Kal?  It is obvious that it had to be destroyed, otherwise Last Battle would be a slaughter instead of a hectic war. 

With Callandor Rand said he was easily holding the power of 100 males.

Yet with CK, he thought he could take on 100-200 damane. 

Then Rand PoV, the amount of power he was holding with the CK when cleansing saidin is equivalent to when he created Dragonmount.    At best LTT when overreaching was probably holding 5-10 times his OP strength imo. 

CK from the titanic amount used at the cleansing, probably equal at least 10,000 men, if not a 100,000.  And to destroy the world, at least that of 100,000 men, if not 1 million.  In the real world, it would the power of nuclear bombs...1 shot kill would a gamma ray burst or the sun going supernova.