What core mechanics are you expecting to be implemented into TS4?

I would like if they gave us the option to put 'Skill Limits' or increase the difficulty in learning certain skills for our Sims. Sometimes, I just want a Sim to not master a skill, without having him giving it up completely.

Example: One of my Sims live in a hut on a secluded island. He's completely hopeless in the kitchen and with said limit, he'd never surpass level 2. Or I would just let it take him five times as long compared to his chef friends. He's an immortal Werewolf, he has the time.