I'm not as well read as I'd like to be, so the only one I've actually had opportunity to do this to so far has been Redwall.
The first one was pretty neat. The second, a bit preachy and repetitive. The third ... well, I returned it to the library on recognising the third or fourth set-piece that was basically exactly the same as in the previous two books, but with slightly different names.
Sorry, Jacques. You gave it a good go, I suppose, but enjoyable fiction simply doesn't consist of running a find-replace and then sending the transformed .doc file off to your publisher when you can find time in between the waterskiing lessons and afternoon of pratting about with a paraglider paid for from the profits of the first book...
Threw my lot in with Pratchett instead after that, and I think I will be there right at the oh so bittersweet end :/ ... ok, he's getting a little bit formulaic as the alzheimers sets in more aggressively, and the narratives are getting a bit looser, but each new book still brings much more to the table in terms of fresh storyline and characterisation than those furry messes. Heck, just compare the Nomes trilogy vs the first three RW books...
I did also get conned into trying some Stephen King, and some Will Self, and got thoroughly sick of both within a hundred pages and just plain gave up. I don't think that counts for the purposes of this actual question though. They were just... annoying. As if you could actually pick up, through the text, the tone of an author who thought they were super-clever and the absolute shit, rather than concentrating on writing an enjoyable and gripping story. I think The Book Of Dave was supposed to be a comedy? Maybe? I seriously couldn't tell, it was just a mess, but one that somehow garnered a lot of critical acclaim. Oddly enough, I have read a couple of SK -shorts- (like Carrie, and Christine...) and found them more enjoyable than the longer book I tried. Maybe he's more suited to doing compact, movie-pitchable works? Certainly the one longer-form thing of his I saw translated into a TV show instead of a movie was diabolically awful...