Akame Ga kill: Introduce a character, dead in one or two episodes. No development in characters and the ultimate goal is to stop the capital from becoming even more shit than what it is. Yet, we keep mentioning this kids friends from someone who wasn't even related to the capital to give him a reason to fight against them. Oh, and hes not even the main character.
Testament: Highschool DxD got a nice little spin off. Its bad enough that you cant enjoy the fanservice due to its censorship, but then you try to make an actual story and develop your characters? I have no idea how this got a season two, yet something like Overlord has a lower possibility.
But yeah, why suggest something bad..?