Since they have already started improving the traits...

From all of the mixed opinions on traits I think people sometimes confuse bad traits for bad AI. Sims 3 traits wasn't anything super spectacular. Sims had a trait and they acted like their traits. The difference is they didn't have the emotion system and the AI of past sims was better. So it made them feel smart and lively in that way.

If those two things don't change in ts4 there is literally no way to make a trait seem "improved" it will just seem extreme. (Which is not a bad thing IMO) that's just my personal conclusion.

But i definitely think more traits are coming.