And I read the last book nearly two years after reading the previous two, which I also read years after the rest of the series. So I don't even remember many of the minor characters, much less their mannerisms or personal details. And with major characters, I still don't remember every exact mannerism, in fact, I most likely just remember the stereotypical ones so even my memory of them is a caricature.
So Sanderson has quite a bit of leeway in his favor, since as far as I'm concerned, he just had to stay true to the spirit of the characters, and had free reign over the unremembered details. And with some characters he succeeded in that. But with others he failed, particularly with Mat. And as I said, all I was asking him was to write the character true to his spirit, fudging all the details. That, surely, isn't an extremely hard thing to do for someone who is a professional author. Instead we got a Mat that is practically illiterate, who saunters or does other stereotypically "rogue"-like things, and so on. Mat is a rogue, it's true, but he was never one to that extent. It's like Sanderson remembered Mat to about the same extent that I do, and then, using my skewed memories skewed some characters even further into the realm of caricatures and stereotypes. And when they're main, critical characters, that is simply unacceptable.
And then he had him try to make up some DnD back stories... Because... Mat's a real big DnD player... How in the world could we all of forgotten that about him?... 
*NM*