Yeah, I was very into this series for a long time.... but around book 5 or so I think he realized that he had a hit series going on and wanted to milk it for all it's worth. Since about book 6 there was no progression in the story line at all. I can't recall exactly which book it was (8-9) but the one where He finally "cleases the taint", an expression which I use for myself as much as I can, was completely worthless till the last chapter.
I gave up after that.