He was pretty much just stuck with the story as Jordon intended/wrote into the ground. I enjoyed Sanderson's Mistborn books, and I don't think his work with WoT was good even by his own standards, but speaking realistically, it must be incredibly hard to gain familiarity with a multitude of characters that you haven't lived and breathed for decades. Only Jordan was capable of keeping them all straight in his head, and even he ended up juggling too many balls, as many of the later books show.

And while some of what you say has merit, and you're certainly entitled to your opinion, I think you're giving far too much credit to Jordon and too little to Sanderson. Particularly, I don't think WoT ever had great or deep characters. They were always fairly one or two-dimensional at best, with most characterized by the amount of sniffing, braid pulling, skirt smoothing, or confused-about-women moments they each had. Sanderson made them even worse, that's definitely true, but if he's a candle then Jordon is certainly no sun.