I agree. They need to be improved, mostly in how they relate to traits and relationships and (the lack of) consequences.
For starters, Fine should probably be the default, not Happy.
Hot-headed sims shouldn't just get randomly angry, but rather overreact to negative events, or simply get angry at what would be mild annoyances for anyone else.
Stuff like that.
But the most important one: can they just not get cripplingly sad for two days when someone they don't even know has died?