If you go into this series without any knowledge of the books then it might be a good series. If you go into this knowing the fundamentals that create the world that TWoT is based in, then be disappointed.
A few points:
The Dragon can only be a man. In the series its stated that the Dragon can be a man or woman. This cannot happen as a fundamental point of the world is that Saidin can only be channeled by men.
Where the heck was Mordeth? I mean, I get that some changes had to be made but Mordeth at Shadar Logoth was pretty important... I suppose its not too important since (I think?) Mashadar was there?
Children of the Light is pretty clearly stated in the book they are primarily a cavalry unit. I think I only saw like 5 horses and everyone else was on foot in the series. Besides, where is all their burnished plate and armor? The whole book is always talking about how they basically shine from a mile off because of how they look.
Loial in the TV series is missing few feet in size... like maybe 5 feet
The One Power CANNOT bring people back from the dead and yet it was done in the TV series. "You are not the creator Rand" <-Remember that line? Which brings up another point, what about Nynaeve's block? Nope, none existent.
This one's not from the book but in the series it seems the One Power is needed to use The Ways, but Fain was able to pass through no problem and he definitely cannot use the power. Its also very obvious that he and Machin Shin never made contact. In fact he never even made contact with Mashadar!
Thom in the books and in the TV series are two completely different characters. Might as well toss out Thom's character and introduce a new one and name him, Edgar.
What happened to all that stuff they found at the Eye of the World? Nothing was found in the TV series! All things they found there were KEY to how the story progresses!
What about Aginor and Balthamel at the Eye of the World? Not to mention the Green man! This is their real first exposure to the Forsaken, but no let's just cut it out completely.
I get it, there are always changes when there's an adaptation which is completely understandable but cutting out major things like, I don't know... how the One Power cannot bring back the dead or killing off Lord Agelmar right away... you know since he's one of the Great Captains. No big deal, we'll just make someone else a Great Captain!
I have to say though, I am looking forward to seeing the Seanchan. They did a decent job with the Trollocs though they are supposed to be half as large again as a normal man (8-9 feet tall I suppose).
Like I said, if you go into the TV series without any prior knowledge of the world that TWoT takes place then it could be good, but with some background into how the world of TWoT works, it cuts out too many things.