I disagree, books 4-6 were the best ones in my opinion. Number 7 was ok. And nr. 8 and 9 were not so great, but still good. CoT is the worst one of the 10, too little Rand and Forsaken, too much Elayne and Perrin.
I just thought Rand was a much more interesting character when he was trying not to channel and just relying on his skill. And Perrin was cool for a while, now he's just whiny.
I agree about Perrin, not about Rand though, I think it's interesting to see how he changes as a person throughout the books. But you've gotta admit, Mat is ten times cooler in the later books compared to books 1-3.