How would you add gameplay depth?

I'd implement something that was in The Sims Medieval: Flaws. For every trait you give your sims in Create-A-Sim, you have to give them a flaw, like you give them a compulsion, or make them really bad at a specific thing that guarantees failure (like if you made them a really bad Gardener, all their plants die or something) or make them dislike people who specifically wear glasses or something.