I know where you're coming from rocker - I kind of fell out of besotted love with Discworld around the time of The Truth
which was when Terry started with the young adults Discworld series (although Thief of Time
are still 2 of my all time faves). I personally think he was getting bored of it around then too and decided to come at it from a different angle, but his life events with his father dying and then the embuggerance have inevitably had their effect as he's definitely a different writer these days (not better or worse particularly, more diversified
What will change things though is this new era with The Watch TV
series, which will be based in canon but start with new storylines too and develop the Watch that way with A-M encapsulated in the New Era of the Patrician and of Moist and other already written citizenry (hopefully we'll see more of UU and foot-the-ball, The Mended Drum, Biers and Harry King and other notable characters making cameo appearances.) Terry's input will be in the infrastructure with Rhianna and Guy Burt supplying the writing for the screenplay. Reading between the lines of recent statements from Terry, Rhianna and Narrativia the new Discworld production company I think that we'll see a tailing off the books altogether over the next few years as Terry rests on his laurels in the Discworld universe at least with his daughter taking the helm on the live action side of things...
Whatever happens in future I think there's enough momentum now with it to carry on after Terry has to stop writing it whether that's sooner or later, so long as people of Rob's, Rhianna's and Guy's calibre are involved.