Here are some of mine:
To make the Forsaken more dangerous I would have less of them killed in the early books
I'd have Rand not love Aviendha and Elayne. He can stay with Min though. I agree with you Elayne's crush on Rand does come of as teenage infatuation.
Kill of Gawyn after Dumai Wells
I would expand the role of Fain, not sure how but he was just such an interesting villain to me that I want to see more of him
Get rid of the Perrin/Faile/Berelain love triangle
At the end, I would have Rand riding of into the sunset on Bela.