It wasn’t really quite that bad. Seasons 1-4 each had quite distinct “survive zombies” scenarios. The season with Terminus was when it started to get dicey: it was quite close to season 2 in terms of theme (“survive zombies while lost in the wild”). Around the end of the first season with Alexandria (6?) is when it effectively stopped being (mainly) about surviving a zombie apocalypse and more about humans fighting each other with some love drama tossed in, oh and some zombies here and there.