enterprise had a really bad ending, because les moonves hated the franchise so he made it a wierd PEGASUS tng sideplot, and it was suppose to have a season 5 to involving the romulan war. nutrek was just terrible from start to finish, animated however was superior to the 3 series, but inferior to old trek.
BSG as well, due to the writer strike, the showrunner forgot about the show and made it a messianic, jesus/god ending. the showrunner hated the sci-finess of the show, so he made them without any advanced tech of the old series.(allegedly the showrunner wanted a mormon themed show.)
Blood of zeus was rushed because netflix cancelled the show.
SPN is another terrible ending, but honestly the show was way past its prime and lifespan anyways.