I didn't enjoy Divergent much (I have only read the first book though) because yeah, the world building felt really terrible. Like I get that she was out to disprove the scenario but it never made any sense to me why the entire world would fall into that? I don't remember the explanation for it but it didn't make sense to me, and some other elements felt cheesy and like something twelve year old me would come up with, without thinking things through at all. It was a while since I read it though, and I didn't like it for several other reasons too which might color my opinion (mostly the main romance was SO PREDICTABLE which is something that annoys me greatly with YA fantasy with female main characters. The romances are almost never appealing to me and always something you can spot from the moment the male character is introduced and I was very very sick of them when I read Divergent).