At the core the sims themselves are broken.
I and many others have said it time and time again. The traits do not matter and the sims are not unique. Each sims trait generates an emotion and all of the sims are in one of the nine emotional state at all times. It is like we have nine traits LOL
We still have no attraction system...really after 5 years there is no attraction system that could have added some uniqueness.
No likes or dislikes system. These sims like everything and are happy about everything even food. Even when they have a fight, they keep on talking as if they were best friends. Who remembers how annoying it was playing the Pleasants with Lilith and Angela fighting every 5 seconds..LOL How ever annoying it was you knew these two HATED each other and there was NO friendly chatter.
We still have sims that do not dance face to face....REALLY after 5 years sims are still kneading the bread in a corner and not dancing with their partner. We still do not have slow dancing.
I feel like these are just SOME BASIC stuff that should be in the game already.