Terry Pratchett - Thud

I just finished reading Thud by Terry Pratchett. I loooove the Discworld but I was rather underwhelmed.

The story was overly preachy and moralising, the plot wasn't exactly thrilling, the dialogue wasn't particularly funny and the dwarves seemed to change quite a lot from previous novels in order to make the story work.

I must admit that I do (on the whole) prefer Pratchett's earlier novels, but I know that he's still got it in him: Jingo, The Truth, The Fifth Element etc.

However, both Monstrous Regiment and Thud were just blah in my opinion... I hope the Discworld isn't in the process of jumping the shark, but I suspect it might be.