Formerly decent-to-good writers whose works over time have degenerated into repetitive authorial tics and stylistic cliché to the point of near self-parody, whom I nevertheless keep up with out of sheer morbid curiosity about series developments (via the library, though, not out of my own funds anymore).
There's a blog out there with a photoshopped cover of one of Mercedes Lackey's Valdemar books which replaces the title with "
My Little Pony Goes to War" and it is so, so true.
Also the ones who've/whose estates have been farming out the actual writing of the sequels "based on extensive notes and outlines" to their popular works to other writers of varying degrees of skill/ability to replicate the appealing portions of the original author's style.
Cf. Anne/Todd McCaffrey, David Eddings, Marion Zimmer Bradley, etc.