TS4 has a lack of continuity. Everything is half formed ideas. There's no consequence for actions, there's no individual personality. A bad thing can happen in front of your sim, and they barely react, and have forgotten about it by the time they walk into the next room (being walked in on in the bathroom seems to be the only exception).
I suspect part of the problem is because they have different teams working on different things, but those teams don't overlap on how to improve the concepts they're working on. And obviously, the biggest part pf the problem comes from developers who don't play the game for fun.
