The first book was a bit uneven, but after that Jordan found a very compelling and entertaining story that was moving quickly and structured to move to a tumultuous climax at the end of each book. The story had tremendous potential, and after each book from 2-6, I closed the book saying, "Wow, I can't wait for the next one". (For clarity's sake, I should point out that I didn't have to wait to move to 3 and 4 from 2)

Book 7 was uneven again, and then 8-11 (and especially 10, as you noted) completely collapsed under the weight of a series of side stories that crippled the plot and hobbled the pacing. Defenders of Jordan start at this point to talk about story arcs and serialization and a whole lot of other things that reek of blind apologetics.

The simple truth is that even before he died, Jordan managed to ruin his series. His death simply made it impossible that the glory of Books 2-6 could be recovered. Sanderson has written some great books on his own, but he's constrained by notes and ideas that Jordan left and has to somehow vomit it all out on paper so that the fans get an ending.

Once that ending is out for everyone to read, Wheel of Time is likely to be used mostly for instructional purposes - a long list of "don'ts" for aspiring writers.