Not trying to be a misery guts, but I've never seen the point in adapting Terry's books to a visual medium, simply because he puts so much work into his narrative and prose which is impossible to put across in film.
None of the adaptations so far (film, animation, etc) have come anywhere near the quality of the books which they are based on.
The only positive aspect of filmed adaptations is as a promotion for the books, but based on the output so far and if seen with no knowledge of Discworld, all of the adaptations would have put me OFF buying the books.
But hey, maybe it's just me.