I'm running into the same sort of thing right now with my game. One of the things that I'm changing is switching from long lifespans to normal. I normally play by seeing how many big things I can complete with one sim and it feels repetitive when I go to play other sims with the same goals or aspirations so I'm trying to mix up my goals for them. I also am trying to give each sim a background story that is integrated with the rest of the world. I noticed in the Sims 2 I really liked how all the households knew each other and had history, so I'm trying to build that as well.
