I really don't agree with moving this topic. Its an issue Brandon brought up on his own blog. Wouldn't it make sense to discuss it in the Brandon Sanderson forum? Plus, he's made more than one post about it and he is finishing the Wheel of Time, like it or not to those fans/friends of his, some of whom obviously don't seem to like that fact.
As for characters who have changed my feelings about them, there are several, but the boys especially.
Rand: Started as sympathetic, but his close minded nature makes him less likeable. Of course, it could be the taint changing his personality along with the stress of leadership, so I'm willing to cut him some slack.
Mat: Gone from my least favorite of the boys, to my favorite character period. He did his best to shirk responsibility in the beginning, but the transformation for me took place in the fifth book. It wasn't until we got into the later books when Mat was readily accepting responsbility that I noticed thats where the change in attitude started happening. He still had immature moments in book five, but from book six foward, he's the best.
Perrin: Almost the opposite of Mat, but can't stand him now. He has become too whiny for my taste. He's no longer the slow thinking, deliberate acting person. Before he was almost like Loial, the gentle giant. Faile has brought out the worst in him. Now he almost loses his temper as fast as Rand, and without the taint to blame. When I re-read the series now, I now have future knowledge of what he's going to do, and it makes it more frustrating to read him early.