I know this isn't an entire TV show, but the Boondocks Season 4 is hot garbage. This is worse than other shows that jumped the shark because with the Boondocks, each season was better than the last with Season 3 being the peak. Season 4 came along and then took a shit all over it. It's like an entirely different show or a bootleg if you will, hate to go with food metaphors but it's like eating a really good meal for a few years but then eating the same meal but the ingredients were not there that made it good but it just looks the same.
Season 4 had a lot of behind the scenes issues with a producer being backed out, and Sony apparently threw out the main writer and creator because he wasn't writing "fast enough" and then cut the episodes down to 10 from the original 20 episodes. They then replaced the creator as the showrunner with some woman who never worked on the show before and was only known for writing Scrubs while an established writer that was still on, only wrote three episodes.
The show definitely had a massive shift as most of the supporting cast who were what helped make the show quite entertaining were cut out which made it feel smaller. A lot of the characters were butchered or "flanderized" with Granddad being more of an idiot, Huey being a generic comedic straight man, Riley being a dumb kid, and Ruckus somehow being more racist to a point it's not even that funny given his constant pushes to bring back slavery (at one point he had a job as a slaveowner makes sense in context and there were white slaves which was really out of character that he was fine with it given a huge part of Ruckus' entire character revolves around worshipping all white people, but he's fine with white slaves). They also tried an overarching story which didn't work well with a new villain, Ed II who was boring as hell and barely even there to the point he could've been replaced by his dad and it wouldn't have made a difference. The overarching story (which was a generic making money to get out of debt plot) only happened because Granddad was more idiotic than usual and it was just an excuse so the show can have a bunch of wacky hijinks (I will get more into this later). There were also plenty of episodes that relied on pop culture references (Breaking Bad, and the movie "Her" being more notable) and felt really dated which goes against the writing philosophy for the first three seasons which were written so they could be timeless episodes. They rehashed two episodes from previous seasons, one of which tried to be cute by making a self-aware jab which still doesn't excuse rehashing an old episode.
The wacky hijinks angle this season went for was dumb as while Boondocks was really ridiculous in many ways, the episodes were mostly social commentary about varying issues that still go on to this day and turning it into wacky hijinks just turns The Boondocks from a stand-out show to a generic adult animated sitcom which it never was. It is like after the Simpsons golden age, it immediately went into the Zombie/Post-Mortem age of the Simpsons we see today rather than a gradual decline. The whiplash is massive and it really is clear Season 4 is an entirely different show.
EDIT: Not to mention, the social commentary in Season 4 is basic and just boiled down to "Racism bad", "Making fun of the disabled bad", and "Slavery bad"
Overall, that season I couldn't even call the Boondocks since Season 4 had most of the writing staff gone save for one guy who wrote less than half the episodes, a new showrunner who clearly didn't understand the show she was running and treated the show as a generic adult animated sitcom, most of the supporting characters being non-existent, and the voice actors sounded like they were phoning in their performance, clearly not enjoying what they were doing. I hope Season 5 goes in a better direction especially with the modern political age giving lots of good material and the original creator returning back.