Ok... I have actually read the entire series, several times. I'm quite taken with it in fact. Obviously a literary work as vast and dense as WoT requires editing and adaptation to convert to performance media. However, this is not an "adaptation", nor is it merely edited to facilitate the media. It is a complete bastardization. The casting is not the issue, the issue is the hubris the writers have to completely rewrite the personalities, motivations and base "character" of the characters. Nearly every character has been rewritten to behave in ways the characters as presented by R. J. would never have behaved. The physical appearance of the characters is irrelevant to that. Again, the casting is NOT the problem. The casting is acceptable. The actors are doing an adequate job of portraying these roles as they've been presented by their employers. While there have been multiple articles and interviews claiming that those in charge of this production are avid fans of the written series, the work they've presented appears as if they haven't actually read the source material. It looks as if they might have skimmed the cliff's notes once, maybe scrolled through a few pages of a wiki about it, made a list of names and a couple plot points then completely made the rest up.
If you're a fan, be prepared for disappointment. If you're new to WoT understand that what you're getting here is not a strong representation of the original work. If you enjoy it, great! Try reading the series or check out the audio book if you want more. Jordan created a world that is wide and nuanced. There are flaws as no work is perfect, but if you actually do enjoy this series and enjoy reading, give the original a try. There is a lot more to it.