I'm by no means an "expert" of the Wheel of Time books. I have read it like 3 times. I have watched the series an equal amount of time, probably more. With only 8 episodes per season and maybe 8 seasons allowed, the biggest mistake made in my honest opinion was adding scenes and happenings that didn't happen but removing things that did.
A list of things I didn't care for:
1. The changes to Mats family and Mat himself were, for me personally, blasphemy! His family were well thought of and loved and he was not a criminal, just a prankster.
2. Perrin did not need a wife or a death to be Eeyore! He was always going to struggle with the use of violence to protect the ones he loved.
3. Rand should have been the main character. Period
4. Moiraine and Landfear should have gone through the red door frame and been gone for a few seasons just like in the books. Don't get me wrong, the actresses playing those 2 were amazing and I would have missed seeing them for several seasons but it leads to other arcs.
5. Changing the relationships of Rand with Min, Aviendha and Elayne. It didn't appear to me he was ever going to actually hook up with any of the three.
6. Not using Saidin/Saidar from day 1.
7. No sword training for Rand, no build-up of Rand's relationship with Lan.
9. Would have prefered to see Mat go through his 2 events rather just 1 to get his gifts.
Things I liked about the changes:
1. Backstories for the Foresaken were awesome. I actually really appreciated how they made you actually like them or at least love to hate them. I loved Lanfear, Ishy and Mogi. Actually I loved all of the Foresaken we got to see.
2. More personality for Alanna. I loved her character and the actress who played her was a doll.
3. I loved seeing the bts for the stuff that happened in the rings.
4. I loved the scenes with Mogi and Elayne/Nynaeve. Especially while under Mogi's influence.
5. I did enjoy the scene with the Eelfinn or whichever one it was, that was creepy and fun.
I just really wish they would have used the time they had to put in as much important stuff from the books and left out scenes that never happened instead. Other than the ones I listed. I'm super happy I got to see my favorite book series come to life and I'm so disappointed to not get more. I just wish some things would have been left alone and not changed so much. Overall I loved season 3, and liked seasons 1 and 2. Will I rewatch it? Yes absolutely, probably a lot since I might not get more.
I really would love to see someone make an animated series so as to not have many limitations. Also it could have more episodes and seasons. Just my 2 cents. π