Does The Sims 4 require a trait overhaul?

YES, but like I mentioned in another thread, the whole system is designed around EMOTIONS and not traits like in The Sims 3, so they'd have to go and pretty much rewrite a huge chunk of the code to add checks for the different traits to actually make them matter in big and small ways in-game. I doubt they'll do that at this point. There's only 2 or so years of content left for The Sims 4. It's probably not worth the investment.